情态动词表推测用法小结.doc

情态动词表示推测的用法1.用于肯定的推测:must can could may might1)其中must语气最强最肯定，只用于肯定句，意为“一定，准是，必然会”。 You havent eaten anything since this morning，you must behungry.2) can次之一般表示理论上可能性,但实际未必会发生。意为“可能”。 Even experienced teacherscanmake mistakes.3) could再次之，意为“可能”My book has disappeared. Who could have taken it?4) may / might语气最弱,表示无把握的推测，意为“可能，或许”。(might比may更加不肯定，更无把握)。例如：Hemay/might be writinga letter now, but Im not sure.2. 用于否定的推测cant couldnt may not might not1)cant用于否定推测，是语气最强的否定推测，意为“不可能，一定不(是)”。Hecanther here because she is in hospital.2）couldnt 比cant 语气弱，表示某事不可能真实，但自己也不是很肯定。It couldnt possibly be Tom. He should be at school now.3). may not/ might not表示否定推测时，表示(无把握的)否定推测，意为“可能/或许不”。例如：It still early. Hemay/might not come back.3.用于疑问句的推测，一般只用can/couldWho can it be at the door? Can it be Tom?