Every possible means ______ to prevent the air pollution, but the sky is still not clear.
| A．is used | B．are used | C．has been used | D．have been used |
Experience is a great _______ when you’re looking for a job.
| A．chance | B．importance |
| C．assistant | D．advantage |
Since you have such good preparations, there ____ be any problem about passing the coming job interview.
| A．mustn’t | B．shan;t | C．shouldn’t | D．needn’t |
We _____ finish it ahead of time, though it was such a tough task.
A. could B. would C. were able to C. ought to
----Was he present a the meeting?
---- He ____ not have attended it, for he was busy repairing his computer all the time.
| A．can | B．might | C．must | D．should |
---- Isn’t amazing that such a good player ____ have failed to be elected to compete?
----Yes, but that is life.
| A．would | B．might | C．must | D．should |