diff --git a/solutions/basic-types/char-bool.md b/solutions/basic-types/char-bool.md
index e69de29..4920211 100644
--- a/solutions/basic-types/char-bool.md
+++ b/solutions/basic-types/char-bool.md
@@ -0,0 +1,75 @@
+1.
+```rust
+use std::mem::size_of_val;
+fn main() {
+    let c1 = 'a';
+    assert_eq!(size_of_val(&c1),4); 
+
+    let c2 = '中';
+    assert_eq!(size_of_val(&c2),4); 
+} 
+```
+
+2.
+```rust
+fn main() {
+    let c1 = '中';
+    print_char(c1);
+} 
+
+fn print_char(c : char) {
+    println!("{}", c);
+}
+```
+
+3.
+```rust
+fn main() {
+    let _f: bool = false;
+
+    let t = false;
+    if !t {
+        println!("hello, world");
+    }
+} 
+```
+
+4.
+```rust
+fn main() {
+    let f = true;
+    let t = true || false;
+    assert_eq!(t, f);
+}
+```
+
+5.
+```rust
+fn main() {
+    let v0: () = ();
+
+    let v = (2, 3);
+    assert_eq!(v0, implicitly_ret_unit())
+}
+
+fn implicitly_ret_unit() {
+    println!("I will returen a ()")
+}
+
+// don't use this one
+fn explicitly_ret_unit() -> () {
+    println!("I will returen a ()")
+}
+```
+
+6.
+```rust
+use std::mem::size_of_val;
+fn main() {
+    let unit: () = ();
+    // unit type does't occupy any memeory space
+    assert!(size_of_val(&unit) == 0);
+}
+```
+
+
diff --git a/solutions/basic-types/functions.md b/solutions/basic-types/functions.md
index e69de29..770c93f 100644
--- a/solutions/basic-types/functions.md
+++ b/solutions/basic-types/functions.md
@@ -0,0 +1,55 @@
+1.
+```rust
+fn main() {
+    // don't modify the following two lines!
+    let (x, y) = (1, 2);
+    let s = sum(x, y);
+
+    assert_eq!(s, 3);
+}
+
+fn sum(x: i32, y: i32) -> i32 {
+    x + y
+}
+```
+
+2.
+```rust
+fn main() {
+    print();
+}
+
+// replace i32 with another type
+fn print() -> () {
+    println!("hello,world");
+}
+```
+
+3.
+```rust
+fn main() {
+    never_return();
+}
+
+fn never_return() -> ! {
+    // implement this function, don't modify fn signatures
+    panic!("I return nothing!")
+}
+```
+
+```rust
+fn main() {
+    never_return();
+}
+
+use std::thread;
+use std::time;
+fn never_return() -> ! {
+    // implement this function, don't modify fn signatures
+    loop {
+        println!("I return nothing");
+        // sleeping for 1 second to avoid exhausting the cpu resoucre
+        thread::sleep(time::Duration::from_secs(1))
+    }
+}
+```
\ No newline at end of file
diff --git a/solutions/basic-types/statements.md b/solutions/basic-types/statements.md
index e69de29..dfc210a 100644
--- a/solutions/basic-types/statements.md
+++ b/solutions/basic-types/statements.md
@@ -0,0 +1,47 @@
+1.
+```rust
+fn main() {
+    let v = {
+        let mut x = 1;
+        x += 2
+    };
+ 
+    assert_eq!(v, ());
+ }
+```
+
+```rust
+fn main() {
+    let v = {
+        let mut x = 1;
+        x += 2;
+        x
+    };
+
+    assert_eq!(v, 3);
+}
+```
+
+2.
+```rust
+fn main() {
+    let v = {
+        let x = 3;
+        x
+    };
+ 
+    assert!(v == 3);
+}
+```
+
+3.
+```rust
+fn main() {
+    let s = sum(1 , 2);
+    assert_eq!(s, 3);
+}
+
+fn sum(x: i32, y: i32) -> i32 {
+    x + y
+}
+```
\ No newline at end of file
diff --git a/src/basic-types/char-bool-unit.md b/src/basic-types/char-bool-unit.md
index 9bf7f75..98f104c 100644
--- a/src/basic-types/char-bool-unit.md
+++ b/src/basic-types/char-bool-unit.md
@@ -1,7 +1,7 @@
 # Char, Bool and Unit
 
 ### Char
-🌟
+1. 🌟
 ```rust, editable
 
 // make it work
@@ -15,7 +15,7 @@ fn main() {
 } 
 ```
 
-🌟
+2. 🌟
 ```rust, editable
 
 // make it work
@@ -30,7 +30,7 @@ fn print_char(c : char) {
 ```
 
 ### Bool
-🌟
+3. 🌟
 ```rust, editable
 
 // make the println! work
@@ -44,7 +44,7 @@ fn main() {
 } 
 ```
 
-🌟
+4. 🌟
 ```rust, editable
 
 // make it work
@@ -57,7 +57,7 @@ fn main() {
 
 
 ### Unit type
-🌟🌟
+5. 🌟🌟
 ```rust,editable
 
 // make it work, don't modify `implicitly_ret_unit` !
@@ -78,7 +78,7 @@ fn explicitly_ret_unit() -> () {
 }
 ```
 
-🌟🌟 what's the size of the unit type?
+6. 🌟🌟 what's the size of the unit type?
 ```rust,editable
 
 // modify `4` in assert to make it work
diff --git a/src/basic-types/functions.md b/src/basic-types/functions.md
index 67ddb47..bab0197 100644
--- a/src/basic-types/functions.md
+++ b/src/basic-types/functions.md
@@ -1,11 +1,11 @@
 # Functions
-🌟🌟🌟
+1. 🌟🌟🌟
 ```rust,editable
 
 fn main() {
     // don't modify the following two lines!
     let (x, y) = (1, 2);
-    let s = sum(1, 2);
+    let s = sum(x, y);
 
     assert_eq!(s, 3);
 }
@@ -16,7 +16,7 @@ fn sum(x, y: i32) {
 ```
 
 
-🌟🌟
+2. 🌟
 ```rust,editable
 fn main() {
    print();
@@ -29,15 +29,16 @@ fn print() -> i32 {
 ```
 
 
-🌟🌟
+3. 🌟🌟🌟
 
 ```rust,editable
+// solve it in two ways
 fn main() {
     never_return();
 }
 
 fn never_return() -> ! {
-    // implement this function, don't modify fn signatures
+    // implement this function, don't modify the fn signatures
     
 }
 ```
diff --git a/src/basic-types/statements-expressions.md b/src/basic-types/statements-expressions.md
index bbaf2e3..c144912 100644
--- a/src/basic-types/statements-expressions.md
+++ b/src/basic-types/statements-expressions.md
@@ -25,9 +25,9 @@ fn main() {
 ```
 
 ### Exercises
-🌟🌟
+1. 🌟🌟
 ```rust,editable
-// make it work with two ways: both modify the inner {}
+// make it work with two ways
 fn main() {
    let v = {
        let mut x = 1;
@@ -38,7 +38,7 @@ fn main() {
 }
 ```
 
-🌟
+2. 🌟
 ```rust,editable
 
 fn main() {
@@ -48,10 +48,13 @@ fn main() {
 }
 ```
 
-🌟
+3. 🌟
 ```rust,editable
 
-fn main() {}
+fn main() {
+    let s = sum(1 , 2);
+    assert_eq!(s, 3);
+}
 
 fn sum(x: i32, y: i32) -> i32 {
     x + y;
diff --git a/zh-CN/src/basic-types/char-bool-unit.md b/zh-CN/src/basic-types/char-bool-unit.md
index b464c52..9437bda 100644
--- a/zh-CN/src/basic-types/char-bool-unit.md
+++ b/zh-CN/src/basic-types/char-bool-unit.md
@@ -1,7 +1,7 @@
 # 字符、布尔、单元类型
 
 ### 字符
-🌟
+1. 🌟
 ```rust, editable
 
 use std::mem::size_of_val;
@@ -14,7 +14,7 @@ fn main() {
 } 
 ```
 
-🌟
+2. 🌟
 ```rust, editable
 
 fn main() {
@@ -28,7 +28,7 @@ fn print_char(c : char) {
 ```
 
 ### 布尔
-🌟
+3. 🌟
 ```rust, editable
 
 // 让  println! 工作
@@ -42,7 +42,7 @@ fn main() {
 } 
 ```
 
-🌟
+4. 🌟
 ```rust, editable
 
 fn main() {
@@ -54,7 +54,7 @@ fn main() {
 
 
 ### 单元类型
-🌟🌟
+5. 🌟🌟
 ```rust,editable
 
 // 让代码工作，但不要修改 `implicitly_ret_unit` !
@@ -75,7 +75,7 @@ fn explicitly_ret_unit() -> () {
 }
 ```
 
-🌟🌟 单元类型占用的内存大小是多少？
+6. 🌟🌟 单元类型占用的内存大小是多少？
 ```rust,editable
 
 // 让代码工作：修改 `assert!` 中的 `4` 
diff --git a/zh-CN/src/basic-types/functions.md b/zh-CN/src/basic-types/functions.md
index 1a07c9e..7015b8e 100644
--- a/zh-CN/src/basic-types/functions.md
+++ b/zh-CN/src/basic-types/functions.md
@@ -5,7 +5,7 @@
 fn main() {
     // 不要修改下面两行代码!
     let (x, y) = (1, 2);
-    let s = sum(1, 2);
+    let s = sum(x, y);
 
     assert_eq!(s, 3);
 }
@@ -29,9 +29,10 @@ fn print() -> i32 {
 ```
 
 
-🌟🌟
+🌟🌟🌟
 
 ```rust,editable
+// 用两种方法求解
 fn main() {
     never_return();
 }
diff --git a/zh-CN/src/basic-types/statements-expressions.md b/zh-CN/src/basic-types/statements-expressions.md
index 671f021..8a066fa 100644
--- a/zh-CN/src/basic-types/statements-expressions.md
+++ b/zh-CN/src/basic-types/statements-expressions.md
@@ -27,7 +27,7 @@ fn main() {
 ### 练习
 🌟🌟
 ```rust,editable
-// 使用两种方法修改内部的 {} 中的内容
+// 使用两种方法让代码工作起来
 fn main() {
    let v = {
        let mut x = 1;
@@ -51,7 +51,10 @@ fn main() {
 🌟
 ```rust,editable
 
-fn main() {}
+fn main() {
+    let s = sum(1 , 2);
+    assert_eq!(s, 3);
+}
 
 fn sum(x: i32, y: i32) -> i32 {
     x + y;