Ⅰ.语法填空
1．—I didn't go to work yesterday because my car broke down.
—You ________have borrowed mine. I wasn't using it then.
答案：could 考查情态动词＋have done。句意：——由于我的车坏了，昨天我没有去上班。——你本来能够用我的车，当时我并不用车。事情发生在过去，could have done本来能够做……，暗含实际上没有做。
2．Sometimes his present job________ be boring, and he has to work for long hours a day.
答案：can 句意：有时他现在的工作有可能很没趣，并且他一天中还必须工作很长时间。can表示事情一时的可能性。
3．We are given a special holiday, so we ________ go to work tomorrow.
答案：needn't 句意：我们有个特别的假期，所以我们明天不必去上班。needn't不必；shouldn't不应该。
4．—Sorry, Professor Smith. I didn't finish the paper yesterday.
—Oh, you ________ have done it as yesterday was the deadline.
答案：should 答语句意：哦，你本该做完的，因为昨天就是最后期限。此处用should have done表示本该做某事而实际上未做。
