第四部分：单项选择（共10小题，每题1分，共10分）
______ for our teachers, we’d never have been able to enter this university.
| A．Had it not been | B．Had it not |
| C．If it was not | D．If he had not been |
If I ________ plan to do anything I wanted to. I’d like to go to Tibet and travel through as much of it as possible.
| A．would | B．could | C．had to | D．ought to |
— Do you know where David is ? I couldn’t find him anywhere.
— Well. He ______ have gone far –his coat’s still here.
| A．shouldn’t | B．mustn’t | C．can’t | D．wouldn’t |
This cake is very sweet. You _____ a lot of sugar in it.
| A．should put | B．could have put | C．might put | D．must have put |
He paid for a seat, when he ______ have entered free.
| A．could | B．would | C．must | D．need |
— The woman biologist stayed in Africa studying wild animals for 13 years before she returned.
— Oh, dear ! She ______ a lot of difficulties !
| A．may go through | B．might go through |
| C．ought to have gone through | D．must have gone through |