Protect your hearing. Don’t wait until you ________ hear a thing.
needn’t
mustn’t
shouldn’t
can’t
The little boy often makes his mother _____him _____.
——would you like somewhere__________? ——No, thanks. I have a big room ________.
What action should they _____________such a thing happen again?
--- Dad, I'm going for Jim's birthday party. I'll be back before 10:00. --- ____________.
---Happy New Year! ---_______.