Look，Tom is crying. I shouldn't have been so harsh on him.

　　⑨本来他能够通过考试，但是他太粗心了。

　　He could have passed the exam，but he was too careless.

　　⑩你本没有必要告诉他们那个事。

　　You needn't have told them that.

　　[链接高考]

　　选词填空

　　1．(2015·福建高考)-Sorry, Mum! I failed the job interview again.

　　-Oh, it's too bad. You should (must/can/should) have made full preparations.

　　解析：句意："对不起，妈妈，我面试又失败了。""噢，那太糟糕了，你应该做好充分准备的。"should have done"本该做......(而实际上未做)"；must have done"一定做了......，表示推测"。can have done用于否定句或疑问句中，也是对发生过的事情的推测。

　　2．(2015·天津高考)I needn't (mightn't/couldn't/needn't) have worried before I came to the new school, for my classmates here are very friendly to me.

　　解析：句意：我来新学校之前本没有必要担心，因为这里我的同学对我非常友好。needn't have done"本没有必要做某事"，表示实际上已经做了某事。根据句意可知应选needn't。

　　3．(2014·陕西高考) My book，The House of Hades, is missing. Who could (need/must/could) have taken it?

　　解析：第二句句意：可能是谁拿走了呢？ could可表示说话者主观猜测的"可能"，此时用于否定句和疑问句中，符合题意。

　　4．(2013·辽宁高考) Harry is feeling uncomfortable. He must (must/could/should) have drunk too much at the party last night.

　　解析：此处为情态动词表示猜测。句意：Harry感到不舒服，他昨天晚上一定喝得太多。由last night可知是对过去的猜测，语气肯定，所以用must have drunk。

　　5．(2013·陕西高考)The children must (should/can/must) have got lost in the woods; otherwise, they would have been at the lakeside camp as scheduled.

　　解析：句意：孩子们一定在树林里迷路了；要不然他们本会按计划到湖边的宿营地的。根据句意可知前句是表示对过去动作的推测，must have done"一定做过某事"，符合句意。

　　6．(2013·四川高考)-Why are your eyes so red？You can't (mustn't/needn't/can't) have slept well last night.

　　-Yeah, I stayed up late writing a report.

　　解析：句意："你的眼睛为什么这么红？你昨晚肯定没睡好"。"是的，我熬夜写了一篇报告。"情态动词表推测，can't have done"不可能做过某事"，符合句意。

　　[针对演练]

　　Ⅰ.用适当的"情态动词＋have done"填空

　　1．You shouldn't/oughtn't to/needn't have helped (help) him, he could do it himself.

　　2．Wang Lin came out. He must have finished (finish) his work.

3．Mike can't have found (find) his bike，for he came to school by bus this morning.