Since nobody gave him any help, he ________ have done the research on his own.

A. can B. must

C. would D. need

When I was a child, I ________ watch TV whenever I wanted to.

A. should B. could

C. must D. need

He ________ sleep, although he tried to, when he got on such a hunt for an idea until he had caught it.

A. wouldn't B. shouldn't

C. couldn't D. mustn't

I should not have laughed if I ________ you were serious.

A．thought B．would think

C．had thought D．have thought

If we ________ a table earlier, we wouldn't be standing here in a queue.

A. have booked B. booked

C. book D. had booked

—You needn't take an umbrella. It isn't going to rain.

—Well, I don't know. It ________do.

A. might B. need

C. would D. should

It ________ be the vocabulary that caused you the problem in the exercise because you know a lot of words.

A．may B．couldn't

C．should D．needn't

Harry is feeling uncomfortable.He ________ too much at he party last night.

A．could drink B．should drink

C．would have drunk D．must have drunk

If he had spent more time practising speaking English before, he ________ able to speak it much better now.

A. will be B. would be

C．has been D．would have been

The door________ open, no matter how hard she pushed.

A. shouldn't B. couldn't

C. wouldn't D. mightn't