选出句中错误并改正。

( ) 1. Is careful. The bus is coming.

　　　　A 　　　　B 　　　　C

( ) 2. John, does your homework quickly!

　　　　　　　A 　B 　　　　　　C

( ) 3. Nancy, please not open the window.

　　　　　A 　　　　B 　　　C

( ) 4. Don't is late for school again.

　　　　　A  B　　 C

( ) 5. Let's us play games together.

　　　　 A　B 　　　C