diff --git a/exercises/14_generics/generics1.rs b/exercises/14_generics/generics1.rs
index 35c1d2fe..f0062fe5 100644
--- a/exercises/14_generics/generics1.rs
+++ b/exercises/14_generics/generics1.rs
@@ -6,9 +6,8 @@
 // Execute `rustlings hint generics1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 fn main() {
-    let mut shopping_list: Vec<?> = Vec::new();
+    let mut shopping_list: Vec<&str> = Vec::new();
     shopping_list.push("milk");
 }
diff --git a/exercises/14_generics/generics2.rs b/exercises/14_generics/generics2.rs
index 074cd938..e43b2a71 100644
--- a/exercises/14_generics/generics2.rs
+++ b/exercises/14_generics/generics2.rs
@@ -6,14 +6,13 @@
 // Execute `rustlings hint generics2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
-struct Wrapper {
-    value: u32,
+struct Wrapper<T> {
+    value: T,
 }
 
-impl Wrapper {
-    pub fn new(value: u32) -> Self {
+impl<T> Wrapper<T> {
+    pub  fn new(value: T) -> Self {
         Wrapper { value }
     }
 }
diff --git a/exercises/15_traits/traits1.rs b/exercises/15_traits/traits1.rs
index 37dfcbfe..899e1625 100644
--- a/exercises/15_traits/traits1.rs
+++ b/exercises/15_traits/traits1.rs
@@ -7,7 +7,7 @@
 // Execute `rustlings hint traits1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 trait AppendBar {
     fn append_bar(self) -> Self;
@@ -15,6 +15,9 @@ trait AppendBar {
 
 impl AppendBar for String {
     // TODO: Implement `AppendBar` for type `String`.
+    fn append_bar(self)->Self{
+        format!("{}Bar",self)
+    }
 }
 
 fn main() {
diff --git a/exercises/15_traits/traits2.rs b/exercises/15_traits/traits2.rs
index 3e35f8e1..4b0e974b 100644
--- a/exercises/15_traits/traits2.rs
+++ b/exercises/15_traits/traits2.rs
@@ -8,11 +8,16 @@
 //
 // Execute `rustlings hint traits2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
 
 trait AppendBar {
     fn append_bar(self) -> Self;
 }
+impl AppendBar for Vec<String> {
+    fn append_bar(mut self)->Self{
+        self.push("Bar".to_string());
+        self
+    }
+}
 
 // TODO: Implement trait `AppendBar` for a vector of strings.
 
diff --git a/exercises/15_traits/traits3.rs b/exercises/15_traits/traits3.rs
index 4e2b06b0..f1aca263 100644
--- a/exercises/15_traits/traits3.rs
+++ b/exercises/15_traits/traits3.rs
@@ -8,10 +8,11 @@
 // Execute `rustlings hint traits3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 pub trait Licensed {
-    fn licensing_info(&self) -> String;
+    fn licensing_info(&self) -> String{
+        "Some information".to_string()
+    }
 }
 
 struct SomeSoftware {
diff --git a/exercises/15_traits/traits4.rs b/exercises/15_traits/traits4.rs
index 4bda3e57..fa20b75a 100644
--- a/exercises/15_traits/traits4.rs
+++ b/exercises/15_traits/traits4.rs
@@ -7,7 +7,7 @@
 // Execute `rustlings hint traits4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 pub trait Licensed {
     fn licensing_info(&self) -> String {
@@ -23,7 +23,7 @@ impl Licensed for SomeSoftware {}
 impl Licensed for OtherSoftware {}
 
 // YOU MAY ONLY CHANGE THE NEXT LINE
-fn compare_license_types(software: ??, software_two: ??) -> bool {
+fn compare_license_types(software: impl  Licensed, software_two:impl  Licensed) -> bool {
     software.licensing_info() == software_two.licensing_info()
 }
 
diff --git a/exercises/15_traits/traits5.rs b/exercises/15_traits/traits5.rs
index df183805..189e93ae 100644
--- a/exercises/15_traits/traits5.rs
+++ b/exercises/15_traits/traits5.rs
@@ -7,7 +7,6 @@
 // Execute `rustlings hint traits5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 pub trait SomeTrait {
     fn some_function(&self) -> bool {
@@ -30,7 +29,7 @@ impl SomeTrait for OtherStruct {}
 impl OtherTrait for OtherStruct {}
 
 // YOU MAY ONLY CHANGE THE NEXT LINE
-fn some_func(item: ??) -> bool {
+fn some_func(item: impl SomeTrait + OtherTrait) -> bool {
     item.some_function() && item.other_function()
 }
 
diff --git a/exercises/16_lifetimes/lifetimes1.rs b/exercises/16_lifetimes/lifetimes1.rs
index 87bde490..b40fc1c9 100644
--- a/exercises/16_lifetimes/lifetimes1.rs
+++ b/exercises/16_lifetimes/lifetimes1.rs
@@ -8,9 +8,9 @@
 // Execute `rustlings hint lifetimes1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
-fn longest(x: &str, y: &str) -> &str {
+
+fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
     if x.len() > y.len() {
         x
     } else {
diff --git a/exercises/16_lifetimes/lifetimes2.rs b/exercises/16_lifetimes/lifetimes2.rs
index 4f3d8c18..464d5b4f 100644
--- a/exercises/16_lifetimes/lifetimes2.rs
+++ b/exercises/16_lifetimes/lifetimes2.rs
@@ -6,7 +6,6 @@
 // Execute `rustlings hint lifetimes2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
     if x.len() > y.len() {
@@ -22,6 +21,8 @@ fn main() {
     {
         let string2 = String::from("xyz");
         result = longest(string1.as_str(), string2.as_str());
+        //移动打印行
+        println!("The longest string is '{}'", result);
     }
-    println!("The longest string is '{}'", result);
+    
 }
diff --git a/exercises/16_lifetimes/lifetimes3.rs b/exercises/16_lifetimes/lifetimes3.rs
index 9c59f9c0..7803e6cd 100644
--- a/exercises/16_lifetimes/lifetimes3.rs
+++ b/exercises/16_lifetimes/lifetimes3.rs
@@ -5,11 +5,11 @@
 // Execute `rustlings hint lifetimes3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
-struct Book {
-    author: &str,
-    title: &str,
+
+struct Book<'a> {
+    author: &'a str,
+    title: &'a str,
 }
 
 fn main() {
diff --git a/exercises/17_tests/tests1.rs b/exercises/17_tests/tests1.rs
index 810277ac..cfba0109 100644
--- a/exercises/17_tests/tests1.rs
+++ b/exercises/17_tests/tests1.rs
@@ -10,12 +10,13 @@
 // Execute `rustlings hint tests1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 #[cfg(test)]
 mod tests {
     #[test]
     fn you_can_assert() {
-        assert!();
+        // assert!(false);
+        assert!(true);
     }
 }
diff --git a/exercises/17_tests/tests2.rs b/exercises/17_tests/tests2.rs
index f8024e9f..bb8158da 100644
--- a/exercises/17_tests/tests2.rs
+++ b/exercises/17_tests/tests2.rs
@@ -6,12 +6,14 @@
 // Execute `rustlings hint tests2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 #[cfg(test)]
 mod tests {
     #[test]
     fn you_can_assert_eq() {
-        assert_eq!();
+        // assert_eq!(true,false);
+        assert_eq!(true,true);
+        assert_eq!("a","a");
     }
 }
diff --git a/exercises/17_tests/tests3.rs b/exercises/17_tests/tests3.rs
index 4013e384..6d2ada49 100644
--- a/exercises/17_tests/tests3.rs
+++ b/exercises/17_tests/tests3.rs
@@ -7,7 +7,7 @@
 // Execute `rustlings hint tests3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 pub fn is_even(num: i32) -> bool {
     num % 2 == 0
@@ -19,11 +19,11 @@ mod tests {
 
     #[test]
     fn is_true_when_even() {
-        assert!();
+        assert!(is_even(10));
     }
 
     #[test]
     fn is_false_when_odd() {
-        assert!();
+        assert!(!is_even(11));
     }
 }
diff --git a/exercises/17_tests/tests4.rs b/exercises/17_tests/tests4.rs
index 935d0db1..a5e5b9c0 100644
--- a/exercises/17_tests/tests4.rs
+++ b/exercises/17_tests/tests4.rs
@@ -5,7 +5,7 @@
 // Execute `rustlings hint tests4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 struct Rectangle {
     width: i32,
@@ -30,17 +30,20 @@ mod tests {
     fn correct_width_and_height() {
         // This test should check if the rectangle is the size that we pass into its constructor
         let rect = Rectangle::new(10, 20);
-        assert_eq!(???, 10); // check width
-        assert_eq!(???, 20); // check height
+        assert_eq!(rect.width, 10); // check width
+        assert_eq!(rect.height, 20); // check height
     }
 
     #[test]
+    #[should_panic]
     fn negative_width() {
         // This test should check if program panics when we try to create rectangle with negative width
         let _rect = Rectangle::new(-10, 10);
+        
     }
 
     #[test]
+    #[should_panic]
     fn negative_height() {
         // This test should check if program panics when we try to create rectangle with negative height
         let _rect = Rectangle::new(10, -10);
diff --git a/exercises/18_iterators/iterators1.rs b/exercises/18_iterators/iterators1.rs
index 31076bb9..6d84c0af 100644
--- a/exercises/18_iterators/iterators1.rs
+++ b/exercises/18_iterators/iterators1.rs
@@ -9,18 +9,17 @@
 // Execute `rustlings hint iterators1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 #[test]
 fn main() {
     let my_fav_fruits = vec!["banana", "custard apple", "avocado", "peach", "raspberry"];
 
-    let mut my_iterable_fav_fruits = ???;   // TODO: Step 1
+    let mut my_iterable_fav_fruits = my_fav_fruits.iter();   // TODO: Step 1
 
     assert_eq!(my_iterable_fav_fruits.next(), Some(&"banana"));
-    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 2
+    assert_eq!(my_iterable_fav_fruits.next(), Some(&"custard apple"));     // TODO: Step 2
     assert_eq!(my_iterable_fav_fruits.next(), Some(&"avocado"));
-    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 3
+    assert_eq!(my_iterable_fav_fruits.next(), Some(&"peach"));     // TODO: Step 3
     assert_eq!(my_iterable_fav_fruits.next(), Some(&"raspberry"));
-    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 4
+    assert_eq!(my_iterable_fav_fruits.next(), None);     // TODO: Step 4
 }
diff --git a/exercises/18_iterators/iterators2.rs b/exercises/18_iterators/iterators2.rs
index dda82a08..2a743432 100644
--- a/exercises/18_iterators/iterators2.rs
+++ b/exercises/18_iterators/iterators2.rs
@@ -6,7 +6,7 @@
 // Execute `rustlings hint iterators2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 // Step 1.
 // Complete the `capitalize_first` function.
@@ -15,7 +15,7 @@ pub fn capitalize_first(input: &str) -> String {
     let mut c = input.chars();
     match c.next() {
         None => String::new(),
-        Some(first) => ???,
+        Some(first) => first.to_uppercase().collect::<String>()+c.as_str(),
     }
 }
 
@@ -24,7 +24,8 @@ pub fn capitalize_first(input: &str) -> String {
 // Return a vector of strings.
 // ["hello", "world"] -> ["Hello", "World"]
 pub fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
-    vec![]
+    words.iter().map(|v|{capitalize_first(v)}).collect::<Vec<String>>()
+
 }
 
 // Step 3.
@@ -32,7 +33,11 @@ pub fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
 // Return a single string.
 // ["hello", " ", "world"] -> "Hello World"
 pub fn capitalize_words_string(words: &[&str]) -> String {
-    String::new()
+    
+    words.iter()
+    .map(|&word| capitalize_first(word))
+    .collect::<Vec<String>>()
+    .join("")
 }
 
 #[cfg(test)]
diff --git a/exercises/18_iterators/iterators3.rs b/exercises/18_iterators/iterators3.rs
index 29fa23a3..180679aa 100644
--- a/exercises/18_iterators/iterators3.rs
+++ b/exercises/18_iterators/iterators3.rs
@@ -9,7 +9,6 @@
 // Execute `rustlings hint iterators3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 #[derive(Debug, PartialEq, Eq)]
 pub enum DivisionError {
@@ -26,23 +25,37 @@ pub struct NotDivisibleError {
 // Calculate `a` divided by `b` if `a` is evenly divisible by `b`.
 // Otherwise, return a suitable error.
 pub fn divide(a: i32, b: i32) -> Result<i32, DivisionError> {
-    todo!();
+    // todo!()
+    if b ==0 {
+        return Err(DivisionError::DivideByZero)
+    }
+    if a%b == 0{
+        return  Ok(a/b)
+    }else{
+        return Err(DivisionError::NotDivisible(NotDivisibleError{ dividend: a,divisor: b}))
+    }    
 }
 
 // Complete the function and return a value of the correct type so the test
 // passes.
 // Desired output: Ok([1, 11, 1426, 3])
-fn result_with_list() -> () {
+fn result_with_list() -> Result<Vec<i32>, DivisionError>{
     let numbers = vec![27, 297, 38502, 81];
-    let division_results = numbers.into_iter().map(|n| divide(n, 27));
+    let division_results: Result<Vec<i32>, DivisionError> = numbers.into_iter()
+        .map(|n| divide(n, 27))
+        .collect();
+    division_results
 }
 
 // Complete the function and return a value of the correct type so the test
 // passes.
 // Desired output: [Ok(1), Ok(11), Ok(1426), Ok(3)]
-fn list_of_results() -> () {
+fn list_of_results() -> Vec<Result<i32, DivisionError>> {
     let numbers = vec![27, 297, 38502, 81];
-    let division_results = numbers.into_iter().map(|n| divide(n, 27));
+    let division_results: Vec<Result<i32, DivisionError>> = numbers.into_iter()
+        .map(|n| divide(n, 27))
+        .collect();
+    division_results
 }
 
 #[cfg(test)]
diff --git a/exercises/18_iterators/iterators4.rs b/exercises/18_iterators/iterators4.rs
index 79e1692b..9aba53f7 100644
--- a/exercises/18_iterators/iterators4.rs
+++ b/exercises/18_iterators/iterators4.rs
@@ -3,9 +3,11 @@
 // Execute `rustlings hint iterators4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 pub fn factorial(num: u64) -> u64 {
+    // (1..=num).fold(1,|acc,x|acc*x)
+    (1..=num).product()
     // Complete this function to return the factorial of num
     // Do not use:
     // - return
diff --git a/exercises/18_iterators/iterators5.rs b/exercises/18_iterators/iterators5.rs
index a062ee4c..81d9137a 100644
--- a/exercises/18_iterators/iterators5.rs
+++ b/exercises/18_iterators/iterators5.rs
@@ -11,7 +11,6 @@
 // Execute `rustlings hint iterators5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 use std::collections::HashMap;
 
@@ -35,7 +34,7 @@ fn count_for(map: &HashMap<String, Progress>, value: Progress) -> usize {
 fn count_iterator(map: &HashMap<String, Progress>, value: Progress) -> usize {
     // map is a hashmap with String keys and Progress values.
     // map = { "variables1": Complete, "from_str": None, ... }
-    todo!();
+    map.values().filter(|&val|val == & value).count()
 }
 
 fn count_collection_for(collection: &[HashMap<String, Progress>], value: Progress) -> usize {
@@ -54,7 +53,10 @@ fn count_collection_iterator(collection: &[HashMap<String, Progress>], value: Pr
     // collection is a slice of hashmaps.
     // collection = [{ "variables1": Complete, "from_str": None, ... },
     //     { "variables2": Complete, ... }, ... ]
-    todo!();
+    collection.iter().map(|map|{
+        map.values().filter(|&val|val == & value).count()
+    }).sum()
+  
 }
 
 #[cfg(test)]
diff --git a/exercises/19_smart_pointers/arc1.rs b/exercises/19_smart_pointers/arc1.rs
index 3526ddcb..982d0c3c 100644
--- a/exercises/19_smart_pointers/arc1.rs
+++ b/exercises/19_smart_pointers/arc1.rs
@@ -21,7 +21,7 @@
 //
 // Execute `rustlings hint arc1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
+
 
 #![forbid(unused_imports)] // Do not change this, (or the next) line.
 use std::sync::Arc;
@@ -29,11 +29,11 @@ use std::thread;
 
 fn main() {
     let numbers: Vec<_> = (0..100u32).collect();
-    let shared_numbers = // TODO
+    let shared_numbers = Arc::new(numbers); // TODO
     let mut joinhandles = Vec::new();
 
     for offset in 0..8 {
-        let child_numbers = // TODO
+        let child_numbers =Arc::clone(&shared_numbers); // TODO
         joinhandles.push(thread::spawn(move || {
             let sum: u32 = child_numbers.iter().filter(|&&n| n % 8 == offset).sum();
             println!("Sum of offset {} is {}", offset, sum);
diff --git a/exercises/19_smart_pointers/box1.rs b/exercises/19_smart_pointers/box1.rs
index 513e7daa..9def2bc9 100644
--- a/exercises/19_smart_pointers/box1.rs
+++ b/exercises/19_smart_pointers/box1.rs
@@ -18,11 +18,10 @@
 //
 // Execute `rustlings hint box1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
 
 #[derive(PartialEq, Debug)]
 pub enum List {
-    Cons(i32, List),
+    Cons(i32, Box<List>),
     Nil,
 }
 
@@ -35,11 +34,13 @@ fn main() {
 }
 
 pub fn create_empty_list() -> List {
-    todo!()
+    List::Nil
+    
 }
 
+//创建不为空的
 pub fn create_non_empty_list() -> List {
-    todo!()
+    List::Cons(0,Box::new(List::Nil))
 }
 
 #[cfg(test)]
diff --git a/exercises/19_smart_pointers/cow1.rs b/exercises/19_smart_pointers/cow1.rs
index fcd3e0bb..0c27aafd 100644
--- a/exercises/19_smart_pointers/cow1.rs
+++ b/exercises/19_smart_pointers/cow1.rs
@@ -12,7 +12,7 @@
 //
 // Execute `rustlings hint cow1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
+
 
 use std::borrow::Cow;
 
@@ -49,6 +49,8 @@ mod tests {
         let mut input = Cow::from(&slice[..]);
         match abs_all(&mut input) {
             // TODO
+            Cow::Borrowed(_)=>{Ok(())}
+            _ => Err("Expected Borrowed value"),
         }
     }
 
@@ -61,6 +63,8 @@ mod tests {
         let mut input = Cow::from(slice);
         match abs_all(&mut input) {
             // TODO
+            Cow::Owned(_) => Ok(()),
+            _ => Err("Expected owned value"),
         }
     }
 
@@ -73,6 +77,8 @@ mod tests {
         let mut input = Cow::from(slice);
         match abs_all(&mut input) {
             // TODO
+            Cow::Owned(_) => Ok(()),
+            _ => Err("Expected owned value"),
         }
     }
 }
diff --git a/exercises/19_smart_pointers/rc1.rs b/exercises/19_smart_pointers/rc1.rs
index 1b903469..1265a5c9 100644
--- a/exercises/19_smart_pointers/rc1.rs
+++ b/exercises/19_smart_pointers/rc1.rs
@@ -10,7 +10,6 @@
 //
 // Execute `rustlings hint rc1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
 
 use std::rc::Rc;
 
@@ -61,17 +60,17 @@ fn main() {
     jupiter.details();
 
     // TODO
-    let saturn = Planet::Saturn(Rc::new(Sun {}));
+    let saturn = Planet::Saturn(Rc::clone(&sun));
     println!("reference count = {}", Rc::strong_count(&sun)); // 7 references
     saturn.details();
 
     // TODO
-    let uranus = Planet::Uranus(Rc::new(Sun {}));
+    let uranus = Planet::Uranus(Rc::clone(&sun));
     println!("reference count = {}", Rc::strong_count(&sun)); // 8 references
     uranus.details();
 
     // TODO
-    let neptune = Planet::Neptune(Rc::new(Sun {}));
+    let neptune = Planet::Neptune(Rc::clone(&sun));
     println!("reference count = {}", Rc::strong_count(&sun)); // 9 references
     neptune.details();
 
@@ -91,13 +90,13 @@ fn main() {
 
     drop(mars);
     println!("reference count = {}", Rc::strong_count(&sun)); // 4 references
-
+    drop(earth);
     // TODO
     println!("reference count = {}", Rc::strong_count(&sun)); // 3 references
-
+    drop(venus);    
     // TODO
     println!("reference count = {}", Rc::strong_count(&sun)); // 2 references
-
+    drop(mercury);    
     // TODO
     println!("reference count = {}", Rc::strong_count(&sun)); // 1 reference
 
diff --git a/exercises/20_threads/threads1.rs b/exercises/20_threads/threads1.rs
index 80b6def3..df6ca355 100644
--- a/exercises/20_threads/threads1.rs
+++ b/exercises/20_threads/threads1.rs
@@ -8,7 +8,6 @@
 // Execute `rustlings hint threads1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 use std::thread;
 use std::time::{Duration, Instant};
@@ -27,6 +26,7 @@ fn main() {
     let mut results: Vec<u128> = vec![];
     for handle in handles {
         // TODO: a struct is returned from thread::spawn, can you use it?
+        results.push(handle.join().unwrap())
     }
 
     if results.len() != 10 {
diff --git a/exercises/20_threads/threads2.rs b/exercises/20_threads/threads2.rs
index 62dad80d..43531057 100644
--- a/exercises/20_threads/threads2.rs
+++ b/exercises/20_threads/threads2.rs
@@ -7,25 +7,26 @@
 // Execute `rustlings hint threads2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 use std::sync::Arc;
 use std::thread;
 use std::time::Duration;
+use std::sync::Mutex;
 
 struct JobStatus {
     jobs_completed: u32,
 }
 
 fn main() {
-    let status = Arc::new(JobStatus { jobs_completed: 0 });
+    let status = Arc::new(Mutex::new(JobStatus { jobs_completed: 0 }));
     let mut handles = vec![];
     for _ in 0..10 {
         let status_shared = Arc::clone(&status);
         let handle = thread::spawn(move || {
             thread::sleep(Duration::from_millis(250));
             // TODO: You must take an action before you update a shared value
-            status_shared.jobs_completed += 1;
+          let mut status_shared_mut=  status_shared.lock().unwrap();
+          status_shared_mut.jobs_completed += 1;
         });
         handles.push(handle);
     }
@@ -34,6 +35,7 @@ fn main() {
         // TODO: Print the value of the JobStatus.jobs_completed. Did you notice
         // anything interesting in the output? Do you have to 'join' on all the
         // handles?
-        println!("jobs completed {}", ???);
+        let status  = status.lock().unwrap();
+        println!("jobs completed {}", status.jobs_completed);
     }
 }
diff --git a/exercises/20_threads/threads3.rs b/exercises/20_threads/threads3.rs
index 91006bbc..7c44fa2a 100644
--- a/exercises/20_threads/threads3.rs
+++ b/exercises/20_threads/threads3.rs
@@ -3,7 +3,7 @@
 // Execute `rustlings hint threads3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 use std::sync::mpsc;
 use std::sync::Arc;
@@ -31,10 +31,12 @@ fn send_tx(q: Queue, tx: mpsc::Sender<u32>) -> () {
     let qc1 = Arc::clone(&qc);
     let qc2 = Arc::clone(&qc);
 
+    //这里克隆一下，避免使用所有权转移
+    let tx_cloned = tx.clone();
     thread::spawn(move || {
         for val in &qc1.first_half {
             println!("sending {:?}", val);
-            tx.send(*val).unwrap();
+            tx_cloned.send(*val).unwrap();
             thread::sleep(Duration::from_secs(1));
         }
     });
diff --git a/exercises/21_macros/macros1.rs b/exercises/21_macros/macros1.rs
index 678de6ee..87319302 100644
--- a/exercises/21_macros/macros1.rs
+++ b/exercises/21_macros/macros1.rs
@@ -3,7 +3,6 @@
 // Execute `rustlings hint macros1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 macro_rules! my_macro {
     () => {
@@ -12,5 +11,5 @@ macro_rules! my_macro {
 }
 
 fn main() {
-    my_macro();
+    my_macro!();
 }
diff --git a/exercises/21_macros/macros2.rs b/exercises/21_macros/macros2.rs
index 788fc16a..9d3417cd 100644
--- a/exercises/21_macros/macros2.rs
+++ b/exercises/21_macros/macros2.rs
@@ -3,12 +3,14 @@
 // Execute `rustlings hint macros2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 fn main() {
     my_macro!();
 }
 
+
+#[macro_export]
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");
diff --git a/exercises/21_macros/macros3.rs b/exercises/21_macros/macros3.rs
index b795c149..def5e454 100644
--- a/exercises/21_macros/macros3.rs
+++ b/exercises/21_macros/macros3.rs
@@ -5,9 +5,10 @@
 // Execute `rustlings hint macros3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 mod macros {
+    #[macro_export] //导出定义的宏
     macro_rules! my_macro {
         () => {
             println!("Check out my macro!");
diff --git a/exercises/21_macros/macros4.rs b/exercises/21_macros/macros4.rs
index 71b45a09..59b9ee45 100644
--- a/exercises/21_macros/macros4.rs
+++ b/exercises/21_macros/macros4.rs
@@ -3,13 +3,13 @@
 // Execute `rustlings hint macros4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 #[rustfmt::skip]
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");
-    }
+    };
     ($val:expr) => {
         println!("Look at this other macro: {}", $val);
     }
diff --git a/exercises/22_clippy/Cargo.lock b/exercises/22_clippy/Cargo.lock
new file mode 100644
index 00000000..d0fc406e
--- /dev/null
+++ b/exercises/22_clippy/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "clippy3"
+version = "0.0.1"
diff --git a/exercises/22_clippy/Cargo.toml b/exercises/22_clippy/Cargo.toml
new file mode 100644
index 00000000..44dc91f8
--- /dev/null
+++ b/exercises/22_clippy/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "clippy3"
+version = "0.0.1"
+edition = "2021"
+[[bin]]
+name = "clippy3"
+path = "clippy3.rs"
\ No newline at end of file
diff --git a/exercises/22_clippy/clippy1.rs b/exercises/22_clippy/clippy1.rs
index e0c6ce7c4..86b006e0 100644
--- a/exercises/22_clippy/clippy1.rs
+++ b/exercises/22_clippy/clippy1.rs
@@ -9,12 +9,13 @@
 // Execute `rustlings hint clippy1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+
 
 use std::f32;
 
+
 fn main() {
-    let pi = 3.14f32;
+    let pi = std::f32::consts::PI;
     let radius = 5.00f32;
 
     let area = pi * f32::powi(radius, 2);
diff --git a/exercises/22_clippy/clippy2.rs b/exercises/22_clippy/clippy2.rs
index 9b87a0b7..1042f7b5 100644
--- a/exercises/22_clippy/clippy2.rs
+++ b/exercises/22_clippy/clippy2.rs
@@ -3,12 +3,10 @@
 // Execute `rustlings hint clippy2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
     let mut res = 42;
     let option = Some(12);
-    for x in option {
+    while let Some(x) = option{
         res += x;
     }
     println!("{}", res);
diff --git a/exercises/22_clippy/clippy3.rs b/exercises/22_clippy/clippy3.rs
index 5a95f5b8..7c0c0750 100644
--- a/exercises/22_clippy/clippy3.rs
+++ b/exercises/22_clippy/clippy3.rs
@@ -3,28 +3,31 @@
 // Here's a couple more easy Clippy fixes, so you can see its utility.
 // No hints.
 
-// I AM NOT DONE
 
 #[allow(unused_variables, unused_assignments)]
 fn main() {
     let my_option: Option<()> = None;
-    if my_option.is_none() {
-        my_option.unwrap();
-    }
+    // if my_option.is_none() {
+    //     my_option.unwrap(); //这里怎么解决
+    // }
 
     let my_arr = &[
-        -1, -2, -3
+        -1, -2, -3,
         -4, -5, -6
     ];
     println!("My array! Here it is: {:?}", my_arr);
 
-    let my_empty_vec = vec![1, 2, 3, 4, 5].resize(0, 5);
+    // let my_empty_vec = vec![1, 2, 3, 4, 5].resize(0, 5);
+    let mut my_empty_vec = vec![1, 2, 3, 4, 5];
+    my_empty_vec.clear();
+
     println!("This Vec is empty, see? {:?}", my_empty_vec);
 
     let mut value_a = 45;
     let mut value_b = 66;
     // Let's swap these two!
-    value_a = value_b;
-    value_b = value_a;
+    // value_a = value_b;
+    // value_b = value_a;
+    std::mem::swap(&mut value_a, &mut value_b);
     println!("value a: {}; value b: {}", value_a, value_b);
 }
diff --git a/exercises/23_conversions/as_ref_mut.rs b/exercises/23_conversions/as_ref_mut.rs
index 2ba9e3f0..8499e226 100644
--- a/exercises/23_conversions/as_ref_mut.rs
+++ b/exercises/23_conversions/as_ref_mut.rs
@@ -7,25 +7,33 @@
 // Execute `rustlings hint as_ref_mut` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 // Obtain the number of bytes (not characters) in the given argument.
 // TODO: Add the AsRef trait appropriately as a trait bound.
-fn byte_counter<T>(arg: T) -> usize {
+fn byte_counter<T>(arg: T) -> usize 
+where T:AsRef<str>
+{
     arg.as_ref().as_bytes().len()
 }
 
 // Obtain the number of characters (not bytes) in the given argument.
 // TODO: Add the AsRef trait appropriately as a trait bound.
-fn char_counter<T>(arg: T) -> usize {
+fn char_counter<T>(arg: T) -> usize 
+where T:AsRef<str>
+{
     arg.as_ref().chars().count()
 }
 
+//TODO 这里后续看看怎么有其他的方式进行修改
 // Squares a number using as_mut().
 // TODO: Add the appropriate trait bound.
-fn num_sq<T>(arg: &mut T) {
+fn num_sq<T>(arg: &mut T)
+where T:AsMut<u32>
+{
     // TODO: Implement the function body.
-    ???
+    let slice = arg.as_mut();
+    *slice = *slice * *slice
+   
 }
 
 #[cfg(test)]
diff --git a/exercises/23_conversions/from_into.rs b/exercises/23_conversions/from_into.rs
index 60911f3e..4175fa27 100644
--- a/exercises/23_conversions/from_into.rs
+++ b/exercises/23_conversions/from_into.rs
@@ -40,10 +40,36 @@ impl Default for Person {
 // If while parsing the age, something goes wrong, then return the default of
 // Person Otherwise, then return an instantiated Person object with the results
 
-// I AM NOT DONE
-
 impl From<&str> for Person {
     fn from(s: &str) -> Person {
+        if s.len() == 0 {
+            return Person::default();
+        }
+        let s_vec = s.split(",").collect::<Vec<&str>>();
+        if s_vec.len() <2{
+            return Person::default();
+        }
+        let mut persion = Person::default();
+        let name = s_vec[0].to_string();
+        if name.len() == 0 {
+            return Person::default();
+        }
+        let age = s_vec[1];
+
+        if age.len() == 0 {
+            return Person::default();
+        }
+
+        let age = if let Ok(age) = age.parse::<usize>() {
+            age
+        } else {
+            return Person::default();
+        };
+
+        Person {
+            name: name,
+            age: age,
+        }
     }
 }
 
diff --git a/exercises/23_conversions/from_str.rs b/exercises/23_conversions/from_str.rs
index 34472c32..bc806837 100644
--- a/exercises/23_conversions/from_str.rs
+++ b/exercises/23_conversions/from_str.rs
@@ -31,7 +31,6 @@ enum ParsePersonError {
     ParseInt(ParseIntError),
 }
 
-// I AM NOT DONE
 
 // Steps:
 // 1. If the length of the provided string is 0, an error should be returned
@@ -49,12 +48,64 @@ enum ParsePersonError {
 // you want to return a string error message, you can do so via just using
 // return `Err("my error message".into())`.
 
+//没有使用索引获取的
+// impl FromStr for Person {
+//     type Err = ParsePersonError;
+//     fn from_str(s: &str) -> Result<Person, Self::Err> {
+//         if s.is_empty(){
+//             return Err(ParsePersonError::Empty);
+//         }
+//        let mut parts = s.split(",");
+//        if parts.clone().count() !=2{
+//         return Err(ParsePersonError::BadLen);
+//        }
+//        let name= parts.next().unwrap_or("").to_string();
+//        let age  = parts.next().unwrap_or("").to_string();
+//        if name.is_empty() {
+//         return Err(ParsePersonError::NoName);
+//        }
+//        let age = match age.parse::<usize>(){
+//         Ok(age) =>age,
+//         Err(e) =>return Err(ParsePersonError::ParseInt(e))
+//        };
+//        Ok(Person{
+//         name,
+//         age
+//        })
+//     }
+// }
+
+
 impl FromStr for Person {
     type Err = ParsePersonError;
+
     fn from_str(s: &str) -> Result<Person, Self::Err> {
+        if s.is_empty() {
+            return Err(ParsePersonError::Empty);
+        }
+
+        let parts: Vec<&str> = s.split(',').collect();
+
+        if parts.len() != 2 {
+            return Err(ParsePersonError::BadLen);
+        }
+
+        let name = parts[0].to_string();
+        if name.is_empty() {
+            return Err(ParsePersonError::NoName);
+        }
+
+        let age = match parts[1].parse::<usize>() {
+            Ok(age) => age,
+            Err(e) => return Err(ParsePersonError::ParseInt(e)),
+        };
+
+        Ok(Person { name, age })
     }
 }
 
+
+
 fn main() {
     let p = "Mark,20".parse::<Person>().unwrap();
     println!("{:?}", p);
diff --git a/exercises/23_conversions/try_from_into.rs b/exercises/23_conversions/try_from_into.rs
index 32d6ef39..68655a6c 100644
--- a/exercises/23_conversions/try_from_into.rs
+++ b/exercises/23_conversions/try_from_into.rs
@@ -27,7 +27,7 @@ enum IntoColorError {
     IntConversion,
 }
 
-// I AM NOT DONE
+
 
 // Your task is to complete this implementation and return an Ok result of inner
 // type Color. You need to create an implementation for a tuple of three
@@ -40,7 +40,26 @@ enum IntoColorError {
 // Tuple implementation
 impl TryFrom<(i16, i16, i16)> for Color {
     type Error = IntoColorError;
-    fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> {
+    fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> 
+    {
+        let (red,green,blue) = tuple;
+        if red <0 ||red>255{
+            return Err(IntoColorError::IntConversion)
+        }
+        if green <0 ||green>255{
+            return Err(IntoColorError::IntConversion)
+        }
+
+        if blue <0 ||blue>255{
+            return Err(IntoColorError::IntConversion)
+        }
+
+
+        Ok(Color{
+            red:red as u8, 
+            green: green as u8,
+            blue:blue as u8,
+        })
     }
 }
 
@@ -48,6 +67,19 @@ impl TryFrom<(i16, i16, i16)> for Color {
 impl TryFrom<[i16; 3]> for Color {
     type Error = IntoColorError;
     fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> {
+        
+        for &value in &arr {
+            if value < 0 || value > 255 {
+                return Err(IntoColorError::IntConversion);
+            }
+        }
+       let arr =  arr.iter().map(|f|*f as u8).collect::<Vec<u8>>();
+        
+        Ok(Color{
+            red:arr[0],
+            green:arr[1],
+            blue:arr[2],
+        })
     }
 }
 
@@ -55,6 +87,20 @@ impl TryFrom<[i16; 3]> for Color {
 impl TryFrom<&[i16]> for Color {
     type Error = IntoColorError;
     fn try_from(slice: &[i16]) -> Result<Self, Self::Error> {
+        if slice.len() ==3{
+            for &value in slice {
+                if value < 0 || value > 255 {
+                    return Err(IntoColorError::IntConversion);
+                }
+            }
+            Ok(Color{
+                red:slice[0] as u8,
+                green:slice[1] as u8,
+                blue:slice[2] as u8,
+            })
+        }else{
+            return Err(IntoColorError::BadLen);
+        }
     }
 }
 
diff --git a/exercises/23_conversions/using_as.rs b/exercises/23_conversions/using_as.rs
index 414cef3a..54c90730 100644
--- a/exercises/23_conversions/using_as.rs
+++ b/exercises/23_conversions/using_as.rs
@@ -10,11 +10,10 @@
 // Execute `rustlings hint using_as` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 fn average(values: &[f64]) -> f64 {
     let total = values.iter().sum::<f64>();
-    total / values.len()
+    total / values.len() as f64
 }
 
 fn main() {
diff --git a/exercises/quiz3.rs b/exercises/quiz3.rs
index 3b01d313..38bd6a40 100644
--- a/exercises/quiz3.rs
+++ b/exercises/quiz3.rs
@@ -16,15 +16,14 @@
 //
 // Execute `rustlings hint quiz3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
 
-pub struct ReportCard {
-    pub grade: f32,
+pub struct ReportCard<T> {
+    pub grade: T,
     pub student_name: String,
     pub student_age: u8,
 }
 
-impl ReportCard {
+impl<T:std::fmt::Display> ReportCard<T> {
     pub fn print(&self) -> String {
         format!("{} ({}) - achieved a grade of {}",
             &self.student_name, &self.student_age, &self.grade)
@@ -52,7 +51,7 @@ mod tests {
     fn generate_alphabetic_report_card() {
         // TODO: Make sure to change the grade here after you finish the exercise.
         let report_card = ReportCard {
-            grade: 2.1,
+            grade:"A+",
             student_name: "Gary Plotter".to_string(),
             student_age: 11,
         };