Eg: 1) The girl might be sleeping this time of day. 2) They may be in the library now.
3.may/might have done 表示对过去发生过的事情的推测， 意为“可能已经做过某事”
Eg: I can’t find my sunglasses. I may/might have left them in your office.
can/be able to
can表示“能够”时与短语be able to同义， 但can只用于一般现在时或过去时，而后 者可用于各种时态。另外，can表示个人 有某种能力，而be able to表示某人通过努 力、克服困难做成某事，相当于succeed in doing sth.；
1. Michael __B__ be a policeman, for he’s much too short.
C. can’t D. needn’t
7. It is usually warm in my hometown, but it _A___be rather
cold sometimes.
A. can B. need
C. dare D. must
8. The fire spread through the hotel very quickly, but everyone ___C____ get away.
情态动词用法总结演示文稿
情态动词的语法特征
1）情态动词表说话人的某种感情或语气，对 某一动作或状态的某种态度。
2) 情态动词不能单独做谓语, 后面只能接动词
原形，ought to和have to除外，。
3) 情态动词没有人称, 数的变化, 但有些情态 动词, 如can、will、have to、may等有过去式。
4. My sister met him at the Grand Theater yesterday
afternoon, so he __A__ your lecture.
A. couldn’t have attended B. needn’t have attended
C. mustn’t have attended D. shouldn’t have attended
1. can 与could
1.表能力,意为“能，能够”，can指现在，could指过去。
1) Some of us can use the computer now, but we couldn’t last year.
2. 表示推测，意为“可能”“或许”，用于疑问句或 否定句，can’t和couldn’t意为“不可能”。
3. ---- I stayed at a hotel while in New York.
---- Oh, did you? You __A__ with Barbara.
A. could have stayed
B. could stay
C. would stay
D. must have stayed
A. were able to B. would
C. was able to D. could
2. may 与might
1. 表示“许可”或“请求”，有“可以”的意思，口语中 常用 might 代 may ,表示委婉语气。 否定回答时用“must not”表“禁止，阻止”， 不用 “may not”. “may not” 表示“可能不” 。
A. needn’t B. can’t C. should D. may
2. Mr. Bush is on time for everything. How __A__ it be
that he was late for the opening ceremony?
A. can B. should
C. may D. must
2) Can she be in the computer center? 3) I though what he said could not be true.
3. 表示“请求” “允许”(表请求时，口语中常用 could 代替 can 使语气更委婉，回答时用can)
4) Can/Could I use your dictionary? 5) Could you lend me a hand?
Eg: 1)--- May I watch TV after supper? --- Yes, you may. / No, you mustn’t. 2) Today is Sunday. She may not in her office now.
2. 表示可能性。 意为“或许，可能” might 比 may 可能性小。
4. can 用于疑问句或否定句中时，表惊异、 不相信等，意思是“可能、能够”。
6) How can you believe such a liar like him?
5. can’t/ couldn’t have done 表示对过去情况的否定推 测,意为“过去不可能做过某事”
7) Susan can’t have written a report like this. 8) She can’t have gone to school, it is Sunday .
5. ThWho __A__it be?
A. can B. need
C. may D. must
6. ----Is Jack on duty today?
----It _C___ be him. It’s his turn tomorrow.
A. mustn’t B. won’t
6. can/could have done表对过去的推测，意为“过去可 能做了某事”。 could have done还可以表示对过去能做 而未做的事情感到惋惜，意为“本能够做某事可事实上 未9）做It”’s a pity. Your class could have got the first prize. 10）Where can Mary have gone?