情态动词在各种时态的用法是怎样的 急用

情态动词在各种时态的用法是怎样的 急用

首先它是动词,而且不同于行为动词,行为动词表示的是可以通过行为来表达的动作（如写,读,跑）,而情态动词只是表达的一种想法（如能,也许,敢）. 　　用法是：情态动词+行为动词原形 　　例句：I can read this sentence in English. 　　我能用英语读这句话. 　　情态动词是一种本身有一定的词义,表示说话人的情绪,态度或语气的动词,但不能单独作谓语,只能和其他动词原形构成谓语. 　　We can be there on time tomorrow.我们明天能按时去那儿. 　　May I have your name? 我能知道你的名字吗? 　　Shall we begin now?我们现在就开始吗? 　　You must obey the school rules.你必须遵守校规. 　　情态动词数量不多,但用途广泛,主要有下列： 　　can (could),may (might),must,need,ought to,dare (dared),shall (should),will (would),have (to),had better. 　　情态动词还有一个很重要的用法,即情态动词表推测—— 　　情态动词表推测的用法小结 　　（一）情态动词表推测的三种句式 　　1．在肯定句中一般用must （一定）,can,could（可能）,might /may（也许,或许）. 　　1．He must/can/may,might know the answer to this question. 　　他一定/可能/也许知道这个问题的答案. 　　2．It is cold in the room. They must have turned off the heating. 　　屋里很冷,他们肯定把暖气关了. 　　2．否定句中用can’t / couldn’t（不可能）,may not/might not（可能不）. 　　1．It can’t/couldn’t be the headmaster. He has gone to America. 　　这不可能是校长,他去美国了. 　　2．He may not/might not know the scientist. 　　他也许不认识那位科学家. 　　3．疑问句中用can/could （能……?）. 　　1．Could he have finished the task? 　　他可能把任务完成了吗? 　　2．Can he be at home now? 　　他现在能在家吗? 　　注：以上三种句式中情态动词的语气按程度都是依次递减的.Might,could并非may,can的过去式,而表示语气较为委婉或可能性较小. 　　（二）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．She must/may/might/could walk miles and miles among the hills without meeting anyone. 　　她一定/可能/也许会在山里一连走好几英里而遇不到一个人. 　　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．Mr. Bush is on time for everything .How can ( could ) he be late for the opening ceremony 　　布什先生一向准时,这次开幕式他怎么可能迟到呢? 　　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. 　　3．Can / Could he have gotten the book? 　　难道他找到书了吗? 　　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： 　　4．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） 　　5．She should / ought to have attended your birthday party,but she had to look after her mother in hospital. （虚拟） 　　她本该出席你的生日晚会的,可是她得在医院照顾她妈妈. 　　6．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. 　　can 和could 表示推测的用法 　　对现在或将来的推测,两者均可用,但can 通常只用于否定句或疑问句中,一般不用于肯定句,而could则可用于肯定句、否定句和疑问句；对过去的推测,应在 can,could 之后接动词的完成式,且此时can仍只用于否定句或疑问句,不用于肯定句；而could 则可用于各种句型.如： 　　Can [Could] this be true? 这能是真的吗 　　Where can [could] he have gone? 他能到哪里去了呢 　　She can’t [couldn’t] have left so soon. 她不可能走得这么早. 　　He could have gone home. 他可能已回家了. 　　注：could后接动词的完成式,除表示对过去的推测外,还可表示过去没有实现的可能性（即某事本来可以发生,却没发生）,或委婉地责备某人过去应该做某事而没有去做（此时不用can）.如： 　　You could have started a little earlier. 你本可早点动身的. 　　You needn’t have cooked it. We could have eaten it raw. 你其实可以不煮熟（它）,我们（本来）可以生吃. 　　can 和could 表示允许的用法 　　表示现在的允许时,若是请求别人允许自己做某事,两者均可用,但用could 语气更委婉；若是自己允许别人做某事,一般只用 can,而不用 could.如： 　　Can [Could] I come in? 我可以进来吗 　　“Could [Can] I use your pen? ” “Yes,of course you can.” “我可以借用你的钢笔吗?”“当然可以.”（不能说Yes,you could.) 　　表示过去的允许时,若表示过去一般性允许（即表示某人随时都可以做某事）,用could；若表示在过去某一特定情况下允许进行某一特定的活动,则不用 could.如： 　　When I lived at home,I could watch TV whenever I wanted to. 我住在家里时,想什么时候看电影就可以什么时候看.（一般性允许） 　　I was allowed to see the film yesterday evening. 昨天晚上允许我去看了电影.（特定的允许,不能用 could) 　　can 和could 表示能力的用法 　　can 表示现在的能力,could 表示过去的能力,要表示将来具备的能力通常 be able to 的将来时态.其中要注意的是,could 表示过去的能力,通常只用于表示过去一般性能力,而不表示过去具体某次特定情形下能够做某事的能力.如： 　　他学习很努力,所以考试能及格. 　　误：He studied hard and could pass the exam. 　　正：He studied hard and was able to pass the exam. 　　注：若在否定句中没有以上限制,即couldn’t 可表示过去特定情况下的能力,如可说 He studied hard but still couldn’t pass the exam.
再问： 情态动词分别在什么时态使用的
再答： 1.1 简单型(Simple)：表示现在或将来的状态 I could work (动词不可加 to ，如：to work。下同) you could work he could work she could work it could work we could work they could work 1.2 完成式型 (Perfect)：表示过去的状态 I could have worked (动词是 have + v-ed 过去分词。下同) you could have worked he could have worked she could have worked it could have worked we could have worked they could have worked 1.3 进行式型 (Continuous)：表示现在或将来还在进行的状态 I could be working (动词是be + v-ing 现在分词。下同) you could be working he could be working she could be working it could be working we could be working they could be working 1.4 完成进行式型 (Perfect Continuous)：表示过去正在进行的状态 I could have been working (动词是 have been + v-ing 现在分词。下同) you could have been working he could have been working she could have been working it could have been working we could have been working they could have been working