must-can-may表示推測的用法PPT課件

1、1must, can, may表示表示“推測推測”的用法的用法2一、對現在的推測一、對現在的推測（一）肯定推測：（一）肯定推測：must be. must be. 一定是一定是.eg: eg: you must be hungry after a long walk. you must be hungry after a long walk. 他們一定正在等我們。讓我們快點。他們一定正在等我們。讓我們快點。eg: they must be waiting for us. lets hurry up. eg: they must be waiting for us. lets hurry up.

2、 （二）否定推測：（二）否定推測：cant be. cant be. 不可能是不可能是.eg: he wears glasses all the time, his eyesight cant be good.eg: he wears glasses all the time, his eyesight cant be good. 你不可能餓了，你剛剛吃過晚飯。你不可能餓了，你剛剛吃過晚飯。eg: you cant be hungry, you have just had dinner. eg: you cant be hungry, you have just had dinner. （三）

3、不確定推測：（三）不確定推測：may be. may be. 可能可能( (不不) )是是.eg: eg: the news may be true, im not sure.the news may be true, im not sure. 她現在可能正在和她的同學們玩。她現在可能正在和她的同學們玩。eg: eg: at the moment she may be playing with her classmates.at the moment she may be playing with her classmates. 3二、對過去的推測二、對過去的推測（一）肯定推測：（一）肯定推測

4、：must have done. must have done. 一定做過一定做過.eg: you must have left your bag in the theatre. eg: you must have left your bag in the theatre. 昨天肯定下過雨了，地面是濕的。昨天肯定下過雨了，地面是濕的。eg: it must have rained last night, the ground is wet.eg: it must have rained last night, the ground is wet.（二）否定推測：（二）否定推測：cant hav

5、e done. cant have done. 不可能做過不可能做過.eg: eg: he doesnt know that book at all, he cant have read it very he doesnt know that book at all, he cant have read it very carefully.carefully. 他不可能殺了人，因為他那時和我在一起。他不可能殺了人，因為他那時和我在一起。eg: he cant have killed the man, because he was with me at that eg: he cant have

6、 killed the man, because he was with me at that time.time.（三）不確定推測：（三）不確定推測：may have done. may have done. 可能做過可能做過.eg: he may have arrived at school. he is the early bird.eg: he may have arrived at school. he is the early bird. anna anna昨天可能見過昨天可能見過tomtom。eg: eg: anna may have seen tom yesterday. an

7、na may have seen tom yesterday. 4從a、b、c、d四個選項中，選出最佳選項。1. jenny _ with him at that time, for i was having dinner with her in my home. a. cant have been b. mustnt have been c. must have been d. may have been2. it is cold in the room. they _ have turned off the heating. a. must b. ought to c. should d.

8、 could3. someone is knocking at the door. it _ be our neighbour. a. may b. cant c. must d. shouldaa54. i didnt hear the phone. i _ asleep. a. must be b. must have been c. should be d. should have been5. johnson _ be a policeman. he is much too short. a. may b. mustnt c. should d. cant6. my friend _ a thief. i believe her. a. cant have been b. cant be c. musnt be d. may be7. who told you the news? i dont remember clearly. it _ mary. it _ mary.