—May I put my car here? —Sorry, you mustn’t. Look at the sign, it says “_______”.

 —Mum, 1 am hungry. May 1 have some______?—Of course. But don't eat too much.

To help the sick people in the hospital is _____ for me .

________mothers can’t go to the meeting ,because they have gone to New York on business.

More often, the air in Hangzhou is dirty because of _____.