Update-Guide.md

@@ -16,7 +16,7 @@
 Here's a typical scenario:
 ``` bash
 user@host:~/repo/blocks$ git checkout <branch>
-(git tells you it won't check out <branch> because you have changes you haven't committed)
+(git tells you it will not check out <branch> because you have changes that have not been committed)
 ```
 
 You now have three choices: