即
would/ could/ should/ might have done
1.--- I stayed at a htel while in New
York.
--- Oh, did you? You ___ with
Barbara.
A. could have stay B. could stay
A. must be C. should be
B. must have been D. should have been
答案B关键词是didn’t，说明动作发生在过去，所以是 对已经发生过的情况的推测判断。
2. --- I rang your home yesterday. A man answered but I didn't recognize the voice. --- On, it ___ my brother, Peter.
C. would stay
D. must have stay
答案 A,本句是一个含蓄虚拟条件句，意思是：If you
had stay at a hotel while in New York, you could have stayed with Barbara. 表达了与过去事实相反的 情况。
2. Yesterday Jane walked away for discussion, otherwise, she ___ something she would regret later.
意思是“可能，或许……”。
她没能及时到达那儿。她可能没赶上 汽车。
She didn’t get there in time. She may have missed the bus.
他今天没来上课，他可能病了。
He didn’t come to school today. He might have been ill.
A. had said B. said C. might say D. might have said
答案D 本句考查的也是含蓄虚拟语气，意思是：如果 她参加了讨论，她可能会说出一些后来令她后悔的话。 表达了与过去事实相反的情况。
二、must have done 表示对过去已经发生过的情况的肯定推
“情态动词＋have done” 重点讲解
如果他学习努力， 他就会通过期末考 试了。
If he had worked hard, he would have passed the Final examination.
一、在虚拟条件句中，如果表示与过去 事实相反的情况，从句用过去完成时， 而主句中则用“情态动词＋现在完成 时”，
1. Sorry, I’m late. I ____ have turned off the alarm clock and gone back to sleep again.
A. might C. can
B. should D. will
2. The window was broken. Tom ____ have
测判断，语气较强， 意思是 “一定……、肯定……”
昨天晚上一定是下雨了，因为今早地 面是潮湿的。
It must have rained last night, for the ground is wet this morning.
1. I didn’t hear the phone. I ____ asleep.
这一定是一次不舒适的旅行。所以，本句表达的是对过去 否定的推测判断，应该用can’t/ could have done来表达。故 答案选D。
2. My sister met him at the Grand Theatre yesterday, so he ____ your lecture.
A. couldn’t have attended B. needn’t have attended C. mustn’t have attended D. shouldn’t have attended
他通过考试了吗？ 不，他不可能通过考试。他学习不努力。
1. --- There were already five people in the car but they managed to take me as well.
--- It ___ a comfortable journey.
A. can’t be
done that, for he was a little naughty.
A. could C. should
B. might D. ought to
四、如果对过去情况推测判断的句 子是疑问 句和否定句，只能用can／could和can’t,／ couldn’t。例如：
他不可能去国外，我一个小时前还见到他 呢。
A. must be C. should be
B. must have been D. should have been
答案B 本句的意思是：我昨天向你家里打的电话。这是对过 去情况的推测判断，应该用must have done结构
三、may/ might have done 也用于对已经发生过的情况的肯 定推测 判断，但语气稍弱，
B. shouldn’t be
C. mustn’t have been D. couldn’t have been
根据They were already five people in the car, but they managed to take me as well.一句中的时态，应该是对过去情况的推测 判断，因为车上已经有5位人了，在带上我一个，可以断定
He can’t have gone abroad; I saw him an hour ago.
He can’t have gone abroad; I saw him an hour ago.
他不可能去国外，我一个小时前还见到他 呢。 --- Can he have passed the exam? --- No, he can’t have. He didn’t work hard.