Tell them ______ the school rules, please.   （ ）

A．obey

B．obeying

C．to obey

D．to obeying

He is very busy. He has no time ______ with his friends. (    )

A．chat

B．chatting

C．to chat

D．chats

选词填空
1. How much ________ (is; are) this book?
2. This is ________ (an; a) email from Tom.
3. I want ________ (send; to send) a postcard to my friend.
4. This postcard ________ (has; have) a panda on it.
5. You can write a letter on ________ (paper; a paper).

I want ______your friend. ( )

A．be

B．to be

C．to

It's our duty not to ________ the environment. （   ）

A．pollute

B．use

C．put

D．polluting