情态动词表推测bymyself.pptVIP

情态动词表推测 情态动词中的can, could, may, might, must都表推测。其中must的可能性最大，can / could次之，may / might 1.对现在的推测 情态动词+ 动词原形 2.对现在正在发生的事情的推测 情态动词+ be doing 3.对过去已发生的事情的推测 情态动词+ have done 一、can 1.can表推测，可能性时，往往用于否定句和疑问句中。 否定句：一定不；不可能 疑问句：会；可能，有时可表示一种惊讶的语气 He can’t be at home. He can’t be sleeping. He can’t have gone to shanghai for i saw him a minute ago. Someone is knocking at the door. Who can it be ? What can/could they be doing? 2.Can有时也可用于肯定句中表推测，意为“有时会” Even experienced teachers can make mistakes. She can be very rude sometimes. It is hot here.but it can be cold in spring. 3.can/could have done 1) 表示对过去情况的推测 He could have gone home. She can’t have left school, for her bike is still here. Why does he know this? Can/could someone have told him about it? 2)表示“本来可以做，而实际上未做” I could have lent you the money.why didn’t you ask me? You could have helped him. I could have done it well, but i wasn’t so careful then. 二. may/might 1. may、might表推测可能性时，意思是“可能、也行” He might/may be American. She may/might be ill. She may/might be doing his homework He may/might have arrived in Beijing. 注意：might不表示过去时态，只是语气上比may更委婉，表示可能性更小。 2 may/might表推测时，可以用于否定句中，意为“可能不、也许不”，但不用于疑问句。 He may/might not be at home. 3.may/might have done 1) 表示对过去行为的推测，意为“可能做过” These studengts may/might have seen the film before. He may/might have arrived in Dalian. 2)might have done 可表示“本可能做而实际上未做” It was really dangerous.i might have killed myself. A lot of men died who might have been saved. 三、must 1.must表推测只能用于肯定句中，意为“想必、一定、必定”表示十分肯定的推测。 You have worked hard all day. You must be tired. He must be very rich. He must be working in the office. Look at his new car. He must have earned a lot of money. 2.must have done 表对过去行为的推测，意为“一定、想必”语气肯定。 I didn’t hear the phone. I must have been asleep They are playing basketball. They must have finished their homework. The road is wet. It must have rained last night. 3.must表推测只能用于肯定句中，否定句疑问句中用can“一定不、肯定不” He must know my address. 他肯定知道我的地址。 （一定） He can`t know my address.