update english doc

Author: wyudong

_posts/en/2020-02-26-Linux（测试版）刷新软件包列表遇到 GPG 错误的解决方法.md

@@ -34,13 +34,13 @@ It can be solved by updating the public key used for verification, or skipping v
 
 The first method you should try is to update the public key, so that the process of verifying the package signature goes smoothly.
 
-Excuting an order
+Run this command to update the public key:
 
 ```shell
 sudo apt-key adv --refresh-keys --keyserver keyserver.ubuntu.com
 ```
 
-Update the public key. After the command is executed successfully, try sudo apt-get update again.
+After the command is executed successfully, try `sudo apt-get update` again.
 
 ### Skip verification