The police still haven’t found her, but they’re doing all they      .

---Did Daniel take my football away?---No, I think it _____ be him, for he doesn’t play football at all.

The funny story makes  us ________ a lot.

 ------ May I smoke here?------ If you____, that's the smoking section over there.

A: May I go out to play football, Dad?B: No, you ________. You must finish your homework first.