Fix some typos and formatting in readme

Readme.md

@@ -1,27 +1,27 @@
 # Rust By Practice
 
-This book was designed for easily diving into Rust，and it's very easy to use: All you need to do is to make each exercise compile without ERRORS and Panics !
+This book was designed for easily diving into Rust, and it's very easy to use: All you need to do is to make each exercise compile without ERRORS and Panics !
 
 > 🎊 Updated on 2022-03-05: Add [Traits](https://practice.rs/generics-traits/traits.html)
 
 ## Read online
 
-- [https://practice.rs](https://practice.rs) 
+- [https://practice.rs](https://practice.rs)
 
 ## Features
-Part of our examples and exercises are borrowed from [Rust By Example](https://github.com/rust-lang/rust-by-example), thanks for your great works! 
+Part of our examples and exercises are borrowed from [Rust By Example](https://github.com/rust-lang/rust-by-example), thanks for your great works!
 
-Although they are so awesome, we also has our own secret weapons :)
+Although they are so awesome, we have our own secret weapons :)
 
 - There are three parts in each chapter: examples, exercises and practices
 
 - Besides examples, we have `a lot of exercises`, you can Read, Edit and Run them ONLINE
-  
-- Covering nearly all aspects of Rust, such as async/await, threads, sync primitives, optimizing and stand libraries** etc
-  
+
+- Covering nearly all aspects of Rust, such as async/await, threads, sync primitives, optimizing and standard libraries** etc.
+
 - Every exercise has its own solutions
-  
-- The overall difficulties are a bit higher, distributed from easy to super hard: easy 🌟  medium 🌟🌟 hard 🌟🌟🌟  super hard 🌟🌟🌟🌟
+
+- The overall difficulties are a bit higher, distributed from easy to super hard: easy 🌟 medium 🌟🌟 hard 🌟🌟🌟 super hard 🌟🌟🌟🌟
 
 **What we want to do is fill in the gap between learning and getting started with real projects.**
 
@@ -37,7 +37,7 @@ struct Point(i32, i32, i32);
 fn main() {
     let v = Point(___, ___, ___);
     check_color(v);
-}   
+}
 
 fn check_color(p: Color) {
     let (x, _, _) = p;
@@ -66,7 +66,7 @@ fn main() {
 
     // ONLY modify this line
     println!("{}, {}, {:?}",f.name, f.data, f);
-} 
+}
 ```
 
 🌟🌟 A match guard is an additional if condition specified after the pattern in a match arm that must also match, along with the pattern matching, for that arm to be chosen.