情态动词有具体的词义，但也同助动词一样，需要与其他词语一起构成句子的谓语，另外情态动词没有人称和数的变化，情态动词后必须跟动词原形。下面英语网小编告诉你英语情态动词用法归纳，大家一起来看看吧!
情态动词+have+过去分词
"情态动词+完成式"(即情态动词+have+过去分词)是高中英语教材中经常出现的动词结构，也是高考试卷非常青睐的项目之一，频频出现在高考试题中。
请看以下高考题：
1、(07陕西)-Where is my dictionary? I remember I put it here yesterday.-You
_____ it in the wrong place.
A must put B should have put C might put D might have put
「分析」答案选D."你可能放错地方了" might have done"可能做过"
2、(06江西)The weather turned out to be fine yesterday. I _____ the trouble to
carry my umbrella with me.
A should have taken B could have taken
C needn't have taken D mustn't have taken
「分析」答案选C.昨天天气晴好，我本不需要带伞。Needn't have done
"本没必要做的，结果却做了"那么，如何掌握它的用法呢?"情态动词+完成式"有时表示对过去或已发生事情的推测，有时表示与过去事实相反的假设以表达后悔、遗憾、责备等情绪。不同的情态动词与动词完成式连用可表示不同的含义，究竟选用哪个情态动词，是推测还是假设，需要结合不同情态动词的基本概念和具体的上下文语境进行分析。现将相关要点叙述如下：
一、must+完成式：表示对过去或已完成行为有把握的推测，意为："一定…过;一定已经…"，仅用于肯定陈述句中。例如：
1) I didn't hear the phone. I ________ asleep. (MET1989)
A. must be B. must have been C. should be D. should have been didn't
提示出是过去时态，因此选择B.
2) Where is my pen?I must have lost it.我的钢笔在哪?我肯定是丢了。
二、can/could+完成式：
1. 肯定式(could)表示与过去事实相反的假设，意为："本来能够/可以…".例如：
3) -I stayed at a hotel while in New York. -Oh， did you? You ________ with
Barbara. (NMET1998)
A. could have stayed B. could stay C. would stay D. must have stayed
解析： A."本可以和Barbara住在一起，没必要住旅店"
4) He went on foot， but he could have gone there by bus.他走着去的，但他本可以坐汽车的。
2. 否定式表示对过去情况的推测，意为："决不会…;决不可能…".例如：
5) -There were already five people in the car but they managed to take me as
well. -It ________ a comfortable journey. (NMET1995)
A. can't be B. shouldn't be C. mustn't have been D. couldn't have been
「分析」答案选D 不可能是很舒服的。有were提示说明发生在过去。
6) My sister met him at the Grant Theatre yesterday afternoon， so he ________
your lecture. (2000上海高考)
A. couldn't have attended B. needn't have attended C. mustn't have attended
D. shouldn't have attended
「分析」答案选A.不可能去听演讲了。
3. 疑问式表示对过去情况的推测或怀疑。例如：
7) Can/Could they have completed their work so soon?
他们能这么快就完成作业了吗?
8) There is no light in the room. Can/Could he have gone out?
屋子没灯光。他出去了?
三、may/might+完成式：
1. 肯定式表示对过去情况的推测,意为："可能已经…"，might表示的可能性比may更加微弱，口气更加委婉。例如：
9) The room is dark; I think he may have gone to bed.
10) You may have noticed that the afternoon sun on a winter's day is low on
the horizon.
请比较：
He may not have said so.(他也许没有这样说过。)
He can't have said so.(他不可能这样说过。)
2. might+完成式也可表示与过去事实相反的假设，意为："本来可以…".例如：
12) He ________ you more help， even though he was busy. (MET1990)
A. might have given B. might give C. may have given D. may give
「分析」答案选A.本可以给予你更多的帮助，即使他很忙。
13) Yesterday， Jane walked away from the discussion. Otherwise， she ________
something she could regret later. (NMET1996)
A. had said B. said C. might say D. might have said
「分析」答案选A.walked说明是过去发生的，所以选择情态动词+完成式
四、should/ought to+完成式：表示与过去事实相反的假设。肯定式表示"本来应该做而未做"，否定式表示"本来不应该做而做了".例如：
14) I told Sally how to get here， but perhaps I ________ for her.
(NMET1994)
A. had to write it out B. must have written it out C. should have written it
out D. ought to write it out
「分析」答案选C.本应该给她写下来
15) I was really anxious about you. You ________ home without a word.
(NMET2001)
A. mustn't leave B. shouldn't have left C. couldn't have left D. needn't
leave
「分析」答案选B.本不应该不吱声就离家
16) Oh， I'm not feeling well in the stomach，I ________ so much fried chicken
just now. (上海2002)
A. shouldn't eat B. mustn't have eaten C. shouldn't have eaten D. mustn't
eat
「分析」答案选C.本不应该吃那么多的炸鸡五、would+完成式：常在虚拟条件句中出现。表示与过去事实相反的假设。例如：
17) -If he ________， he ________ that food. -Luckily he was sent to the
hospital immediately. (NMET1993)
A. was warned; would not take B. had been warned; would not have taken
C. would be warned; had not taken D. would have been warned; had not
taken
「分析」答案选B.这是与过去事实相反的虚拟条件句。要求：if+had done，主语+would/could/should +have done
18) You didn't let me drive. If we ________ in turn， you _______ so tired.
(NMET1996)
A. drove; didn't get B. drove; wouldn't get
C. were driving; wouldn't get D. had driven; wouldn't have got
「分析」答案选D.道理同上。
五、needn't+完成式：表示做了不必做的事情，意为："本不必…;本不需要…".例如：
19) There were plenty of time. She needn't have hurried.
20) You needn't have phoned me just now.
情态动词四大分类
①只做情态动词:may，might，must…
②可做情态动词又可做实义动词：如：need，dare.can...
③具有情态动词特征：have(had,has)to,used to，ought to
④可做情态动词又可作助动词：如：shall(should),will(would)
情态动词的语法特征
1)情态动词不能表示正在发生或已经发生的事情，只表示期待或估计某事的发生。
2)情态动词除ought和have外，后面只能接不带to的不定式。
3)情态动词没有人称，数的变化，即情态动词第三人称单数不加-s。
4)情态动词没有非谓语形式，即没有不定式，分词，等形式。
