diff --git a/en/src/compound-types/string.md b/en/src/compound-types/string.md
index f058271..627ce5e 100644
--- a/en/src/compound-types/string.md
+++ b/en/src/compound-types/string.md
@@ -22,7 +22,7 @@ fn main() {
 
 // Fix the error with at least two solutions
 fn main() {
-    let s: Box<str> =  "hello, world".into();
+    let s: Box<str> = "hello, world".into();
     greetings(s)
 }
 
@@ -54,7 +54,7 @@ fn main() {
 
 // Fix all errors without adding newline
 fn main() {
-    let  s =  String::from("hello");
+    let  s = String::from("hello");
     s.push(',');
     s.push(" world");
     s += "!".to_string();
@@ -102,7 +102,7 @@ Opsite to the seldom using of `str`, `&str` and `String` are used everywhere!
 
 // Fix error with at least two solutions
 fn main() {
-    let s =  "hello, world";
+    let s = "hello, world";
     greetings(s)
 }
 
@@ -117,7 +117,7 @@ fn greetings(s: String) {
 
 // Use two approaches to fix the error and without adding a new line
 fn main() {
-    let s =  "hello, world".to_string();
+    let s = "hello, world".to_string();
     let s1: &str = s;
 
     println!("Success!");
diff --git a/en/src/functional-programing/cloure.md b/en/src/functional-programing/cloure.md
index 7546057..25b77ac 100644
--- a/en/src/functional-programing/cloure.md
+++ b/en/src/functional-programing/cloure.md
@@ -173,7 +173,7 @@ fn main() {
 fn main() {
     let mut s = String::new();
 
-    let update_string =  |str| s.push_str(str);
+    let update_string = |str| s.push_str(str);
 
     exec(update_string);
 
@@ -260,7 +260,7 @@ move closures may still implement `Fn` or `FnMut`, even though they capture vari
 fn main() {
     let s = String::new();
 
-    let update_string =  move || println!("{}",s);
+    let update_string = move || println!("{}",s);
 
     exec(update_string);
 }
@@ -275,7 +275,7 @@ The following code also has no error:
 fn main() {
     let s = String::new();
 
-    let update_string =  move || println!("{}",s);
+    let update_string = move || println!("{}",s);
 
     exec(update_string);
 }
diff --git a/en/src/variables.md b/en/src/variables.md
index 6e70f14..7e092f0 100644
--- a/en/src/variables.md
+++ b/en/src/variables.md
@@ -19,7 +19,7 @@ fn main() {
 
 // Fill the blanks in the code to make it compile
 fn main() {
-    let __ =  1;
+    let __ = 1;
     __ += 2; 
     
     assert_eq!(x, 3);
@@ -73,7 +73,7 @@ fn main() {
 
     assert_eq!(x, 12);
 
-    let x =  42;
+    let x = 42;
     println!("{}", x); // Prints "42".
 }
 ```
diff --git a/solutions/compound-types/string.md b/solutions/compound-types/string.md
index c9edee0..046083f 100644
--- a/solutions/compound-types/string.md
+++ b/solutions/compound-types/string.md
@@ -10,7 +10,7 @@ fn main() {
 
 ```rust
 fn main() {
-    let s: Box<str> =  "hello, world".into();
+    let s: Box<str> = "hello, world".into();
     greetings(&s)
  }
  
@@ -46,7 +46,7 @@ fn main() {
 
 ```rust
 fn main() {
-    let mut s =  String::from("hello");
+    let mut s = String::from("hello");
      s.push(',');
      s.push_str(" world");
      s += "!";
@@ -83,7 +83,7 @@ fn main() {
 
 ```rust
 fn main() {
-    let s =  "hello, world".to_string();
+    let s = "hello, world".to_string();
     greetings(s)
 }
 
@@ -114,7 +114,7 @@ fn main() {
 
 ```rust
 fn main() {
-    let s =  "hello, world";
+    let s = "hello, world";
     let s1: &str = s;
 }
 ```
diff --git a/solutions/functional-programing/closure.md b/solutions/functional-programing/closure.md
index 9bc33a8..86f9e75 100644
--- a/solutions/functional-programing/closure.md
+++ b/solutions/functional-programing/closure.md
@@ -136,7 +136,7 @@ fn main() {
 fn main() {
     let mut s = String::new();
 
-    let update_string =  |str| s.push_str(str);
+    let update_string = |str| s.push_str(str);
 
     exec(update_string);
 
diff --git a/zh-CN/src/compound-types/string.md b/zh-CN/src/compound-types/string.md
index e668464..48cfc1c 100644
--- a/zh-CN/src/compound-types/string.md
+++ b/zh-CN/src/compound-types/string.md
@@ -20,7 +20,7 @@ fn main() {
 
 // 使用至少两种方法来修复错误
 fn main() {
-    let s: Box<str> =  "hello, world".into();
+    let s: Box<str> = "hello, world".into();
     greetings(s)
 }
 
@@ -50,7 +50,7 @@ fn main() {
 
 // 修复所有错误，并且不要新增代码行
 fn main() {
-    let  s =  String::from("hello");
+    let  s = String::from("hello");
     s.push(',');
     s.push(" world");
     s += "!".to_string();
@@ -98,7 +98,7 @@ fn main() {
 
 // 使用至少两种方法来修复错误
 fn main() {
-    let s =  "hello, world";
+    let s = "hello, world";
     greetings(s)
 }
 
@@ -113,7 +113,7 @@ fn greetings(s: String) {
 
 // 使用两种方法来解决错误，不要新增代码行
 fn main() {
-    let s =  "hello, world".to_string();
+    let s = "hello, world".to_string();
     let s1: &str = s;
 }
 ```
diff --git a/zh-CN/src/variables.md b/zh-CN/src/variables.md
index 0febb14..12e1b28 100644
--- a/zh-CN/src/variables.md
+++ b/zh-CN/src/variables.md
@@ -18,7 +18,7 @@ fn main() {
 
 // 完形填空，让代码编译
 fn main() {
-    let __ =  1;
+    let __ = 1;
     __ += 2; 
     
     println!("x = {}", x); 
@@ -69,7 +69,7 @@ fn main() {
 
     assert_eq!(x, 12);
 
-    let x =  42;
+    let x = 42;
     println!("{}", x); // 输出 "42".
 }
 ```