情态动词表推测的三种时态
1对将来情况的推测,用“情态动词+动词原形”。
(1)She must / may / might / could arrive before 5.
5:00前她一定/可能/也许到。
2.对现在或一般情况的推测,用“情态动词+be”,“情态动词+be doing”或“情态动词+动词原形”。
(1)He must/may/might/could be listening to the radio now.
他一定/可能/也许正在听收音机。
(2)He can't(couldn't)/may(might) not be at home at this time.
这个时候他不可能/可能不在家。
3.对过去情况的推测,用“情态动词 + have +过去分词”。
(1)It must/may/might/could have rained last night.The ground is wet.
地湿了,昨晚肯定/可能/也许下雨了。
(2)The door was locked.He can(could)not/may(might)not have been at home.
门锁着,他不可能/可能不在家。
注:情态动词should/ought to表推测时,意为“想必会,理应……”但与“have+过去分词”连用时,则又可构成虚拟语气意为“本应该做某事却没做”。例如:
(3)It's seven o'clock.Jack should/ought to be here at any moment.
现在七点钟了,杰克理应随时到达。(推测)
(4)Tom should not /ought not to have told me your secret,but he meant no harm.(虚拟)
汤姆本不该告诉我你的秘密,可是他并无恶意。