概要： 【注意】表示推测过去某动作发生的可能性时,就表示的可能性程度而言,must最大,could其次,may更次之,might最小。例如: ⑿ ---I wonder how Tom knew about your past. ---He must / could / may / might have heard of it from Mary. 2) 情态动词+动词进行式 情态动词+行为动词进行式(即情态动词+ be + doing形式),表示推测或评论某动作现在是否正在进行。例如: ① He must be playing basketball in the room. ② She may be staying at home. 3) 情态动词+动词完成进行式 情态动词+行为动词完成进行式(即情态动词+ have been + v-ing形式),表示推测或评论过去某动作是否正在进行或一直在进行。例如: ① They should have been meeting to discus
2017届高三英语语法复习教案之情态动词,标签：高三英语复习教案,高三英语备课教案,http://www.67jx.com【注意】表示推测过去某动作发生的可能性时,就表示的可能性程度而言,must最大,could其次,may更次之,might最小。例如:
⑿ ---I wonder how Tom knew about your past.
---He must / could / may / might have heard of it from Mary.
2) 情态动词+动词进行式
情态动词+行为动词进行式(即情态动词+ be + doing形式),表示推测或评论某动作现在是否正在进行。例如:
① He must be playing basketball in the room.
② She may be staying at home.
3) 情态动词+动词完成进行式
情态动词+行为动词完成进行式(即情态动词+ have been + v-ing形式),表示推测或评论过去某动作是否正在进行或一直在进行。例如:
① They should have been meeting to discuss the problem.
② He may / might have been buying stamps in the post office when you saw him.|
三、几组词的辨异
1. can 和be able to
1)情态动词can只有两种时态形式,现在式can和过去式could,而be able to有多种时态形式
Mary can play the piano. She has been able to play it since she was 5.
玛丽会弹钢琴。她五岁起就会弹了。
2)用在过去时中,could经常表示能够做某事,事实上不一定去做,而was / were able to则表示“过去做成了某事”。在否定句中两者可通用。
He could swim across the English Channel. But he didn’t feel like it that day.
他能游过英吉利海峡,但那天他不想游。
Yesterday I was able to get home before the heavy rain. 昨天我在下大雨前赶到了家里。
2. must和 have to语法学习纲要由江苏省靖江高级中学外语组为英语猫网站特供
must表示主观意志,而have to表示由于客观因素不得不做某事。must没有过去式,除在间接引语中可用于表示过去时间,在直接引语中表示过去时间应该用had to代替。
I told her that she must give up smoking. 我叫她必须戒烟。
We had to get everything ready that night. 我们那晚得把一切准备就绪。"
3. would和used to
1)used to表示过去与现在或过去某时与后来的情况有不同,而would只表过去的情况。
People used to think that the earth was flat.
过去人们认为地球是平的。(现在人们不这么认为。)
She would go out for a walk in the morning when she was in the country.
在乡下时,她总是在早晨去散会儿步。(可能现在仍有散步的习惯。)
2)used to可表示过去的习惯动作和经常的情况,而would只表示过去的习惯动作。
He used to ∕would smoke while writing. 过去他写东西时常抽烟。
She used to be fat. 她过去很胖。
◆ 考题剖析
例题1. I didn't hear the phone. I ________ asleep. (NMET 89)
A. must be B. must have been C. should be D. should have been;
答案 B 从原题中的I didn't hear the phone.这一信息可以判断出,用must have
done表示对过去事实的准确的肯定猜测。
例题2. Tom ought not to me your secret ,but he meant no harm. (NMET93)
A. have told B. tell C. be telling D. having told
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