Whenever he worked until midnight, he _____ drink some coffee to get refreshed．

---Mary’s score on the test is the highest in her class.
---Really? She ______ have studied very hard.

He has no money nor friends here. That’s why he ______ sleep in the street.

--It’s said that no one ______ light a cigarette at a gas station.
--- Yes. Safety always comes the first.

— Must I take a taxi?
—No, you______. It is only a six minutes’ walk. 
A. don’t have to             B. must                  C  can’t           D ought to

Living in such a high mountain  _________be cold．

– Is your brother going to Jack’s birthday party tonight?
– I am not sure. He _____ go to the concert with his girlfriend instead.

—You just think of yourself! You kept me wailing for at least three hours．
—I' m sorry that you _____________ think so．

______ it have been the failure to pick up directions from the ground control that caused the air crash?

There _____ be a shortage of water in Yunnan? I wonder. You know it is in the southwest of China where there used to be adequate rain .
A could              B  must            C  can              D should