He be Curnane!He be thinking.He be a common boy.情态动词表推测mustmightcant表推表推测的三种句式的三种句式The light is on, so somebody _ be at home. mustThe light is on, so my sister _ be at home. may/ might 1. 在肯定句中一般用在肯定句中一般用must, may/ might，语气气逐逐渐减弱。减弱。常用于表推常用于表推测的情的情态动词will wouldought toshould（一定）（一定）（可能）（可能）（很有可能）（很有可能）（很有可能）（很有可能）（应该，很有可能），很有可能）（应该，很有可能），很有可能）（可能）（可能）（可能）（可能）（可能）（可能）肯定肯定推推测最最 强最最 弱弱mustmightcancouldmayIts sunny. It _ rain. cant表推表推测的三种句式的三种句式 2.在否定句中用在否定句中用cant/ couldnt(不可能不可能)，may not/ might not(可能不可能不)。He _ know how to answer this question. /might notmay not常用于表推常用于表推测的情的情态动词（禁止禁止,不不许）（可能）（可能）（肯定不肯定不, 不可能不可能）（肯定不肯定不,不不可能）可能）（可能（可能不不）否否定定推推测最最 强最最 弱弱must notmight notcantcouldntmay not（不用于推不用于推测）表推表推测的三种句式的三种句式 3. 在疑在疑问句中，一般只使用句中，一般只使用can/ could。 she have finished her homework? your sister be at home now?CouldCan【口口诀】can不肯，may/ could/ might不问，must不否问注：注：can表示推表示推测时，不用于，不用于肯定句；肯定句；may/might/could表示推表示推测时，不用于疑，不用于疑问句；句；must表示推表示推测时，不用，不用于否定句或疑于否定句或疑问句。句。情态动词表推测的三种时态He _ to music. 对现在或一般情况的推测“情态动词+be”“情态动词+be doing”“情态动词+动词原形”must be listing He _ at home now. The light isnt on. cant beHe _ in his office. may work情态动词表推测的三种时态She _ very happy when she opens the door. 对将来推将来推测，“情情态动词+动词原形原形”must be情态动词表推测的三种时态The ground is wet. It _ yesterday night. 对过去或已去或已经完成的推完成的推测，“情情态动词+have+过去分去分词”may have rained表对已经发生的事情的推测，意为“一定，想必”，在句子中表示的是一种肯定的推测。这种结构一般只用于肯定句。对过去推测的几组用法1. must have done否定形式：否定形式：cant (couldnt) have doneThey out, because the light is still on. He didnt hear the phone. He asleep. “不可能，肯定不会不可能，肯定不会”must have beencant have gone表表对过去的去的时间里可能里可能发生的事情的推生的事情的推测，一般只用于否定句和疑一般只用于否定句和疑问句。句。对过去推测的几组用法2. can/ could have doneHe cant have finished the work so soon.用于肯定句中，常用来表示本来可以完成而用于肯定句中，常用来表示本来可以完成而实际未完成的未完成的动作。作。We could have walked to the station, it was so near. “本来能做本来能做.(而而实际上没做上没做)”1)表对已经发生的事情不太肯定的推测，意为“可能已经，或许已经”对过去推测的几组用法3. may/ might have done2)虚拟用法：表可以做，但却没有做。If we had taken the other road, we might have arrived earlier.He might have given you more help, but he was very busy. 推测三种句式三种句式否定否定否定否定肯定肯定肯定肯定疑疑疑疑问问常用于表推常用于表推测的情的情态动词否定否定否定否定肯定肯定肯定肯定情情态动词表推表推测的三种的三种时态将来将来将来将来现现在在在在/ /一般一般一般一般过过去去去去/ /完成完成完成完成几几组对过去去的的推推测can/ could have donemust have donemay/ might have doneExercise:1. Whose earrings are these? They _ be Marys. She wears earrings sometimes. 2. Carls _ come to the party tonight, but Im not sure. 3. The telephone is ringing, but nobody answer it, he _ be at home.4. -Is this Lan Qiangs boxing glove? -Yes, it _ be his. This is his name on the back. 5. Youd better take an umbrella. It _ rain this afternoon. may/ could/ might must may/ might/ could cant may/might/could 6. Its the library! So you _ know shouting is not allowed here. 7. -Have you decided where to spend your summer holiday? -Not yet. We _ go to Qingdao. 8. -Is Jessica giving us a speech this evening? -No, it _ be her. She has gone to Japan. 9. -What will the weather be like tomorrow? -It _ be rainy, cloudy, or sunny. Who know?10. You _ be tired after playing sports for a long time without a rest.mustmaycantmightmust