1、can,could 1.表能力 （有时态变化）could,would be able to,can,will be able to 2.表允许，在口语中代替 may，有“可以”的意思，could表示的语气更加委婉、客气 3.表示可能性，常用于否定句”不可能”和疑问句”可能吗?”,极少时用于肯定句意为”有时候是”4.can和could接动词的完成形式，表示可能已经做某事。Can一般用在否定和疑问句中,表示不相信、怀疑等态度。may,might 1表示许可或征求对方的许可，有“可以”的意思。might表示的语气更加委婉、客气 问：might,may 答：may/can;mustnt 2表示猜测,m
2、ight 的语气较may弱在肯定句中，may 的可能性比can 高，may 表示现实的可能性，can 表示理论上的可能性。如：The road may be blocked.（长长的车队）（长长的车队）这条路可能不通了。这条路可能不通了。The road can be blocked.（元宵了）（元宵了）这条路可能会是不通的。这条路可能会是不通的。在疑问句中，表示可能性用在疑问句中，表示可能性用can。如：如：Where can he be?他会在哪呢？他会在哪呢？3.表示祝愿;但语气较正式:e.g.May you succeed!May you have a good journey!4.多
3、在间接引语中表示过去的可能和允许。如:She said that he might take her bike.她说他可以拿她的自行车去用。注意，除间接引语，might 一般不表示过去的可能或者许可。如要表示过去的可能可以用couldmust 1必须 肯：must 否：neednt/dont have to 2在否定结构中表不许、禁止 肯：may/can 否：mustnt 3表猜测，暗含有很大的可能性 肯：must 否：cantmust表示对某人某事的猜测，表示对某人某事的猜测，作作“准是准是”，“一定一定”，一般用于肯定句中。对过去发，一般用于肯定句中。对过去发生的事情作肯定判断用生的事情作
4、肯定判断用must have donewill,would will，would用于各种人称，表示“意志”“决心”“允诺”(有时态变化)sb would rather do sth will，would在疑问句中用于第二人称，提出请求或询问，would比will客气委婉would 表示过去反复发生的事shall&should 用于构成将来时是助动词用于构成将来时是助动词【一一】Shall shall用于一三人称征求对方的意见 用于第二三人称表示说话人的允诺、命令或威胁。should should用于表示“应该”“应当”或给建议 Can you drive a car?-Yes,I can.-N
5、o,I cant.你会开车吗？-我会。-我不会。Can I use your bike?我可以用你的自行车吗？Could I come to see you tomorrow?明天我可以来见你吗？问：can,could 答：can/may;cant,mustnt表示与过去表示与过去 有关的能力和推测有关的能力和推测:eg.We all knew that the young man couldnt be a doctor.Can it be true?那会是真的吗？Today is Sunday.He cant be at school.今天是星期天。他不可能在学校里。He can be ni
6、ce.他有时人很好.e.g.They cant have gone out because the light is still on.e.g.They couldnt have gone out because the light was still on.You may go now.你可以走了。May I use your computer?我用一下你的电脑可以吗？Yes,you can/may.No,you mustnt.You may be right.你可能是对的。You may not be right.你可能不对。You cant be right 你肯定不对.Might I
7、use your pen for a while?我能用用你的钢笔吗？Yes,you may/can.No you mustnt.You must talk to them about their study.你必须同他们谈谈关于他们学习的事。You neednt talk to them about their study.(不必)You mustnt leave here.你不能离开这儿。He must be ill.He looks so pale.他肯定是病了。他的脸色那么苍白。He cant be ill.He looks so well.Thereisnobodyhere.They
8、musthaveallgonehome.（不用can have gone）I will try.我愿一试。I would rather go there with you.我要和你一块到那儿去。（表意愿）Dad wouldnt allow it.爸爸不会允许这件事。（表许可）Will you type this,please?请打印这个，好吗？Wont you sit down?请坐下，好吗？Will you stay here for lunch?Sorry,I cant.My brother is coming to see me.Would you help us,please?请您帮助
9、我们，好吗？（表请求）Yes，I will.No I will not.Shall I turn on the light,Mom?妈妈，我把灯打开好吗？（用于征求对方的意见，）Shall I tell her about it?“No,you neednt.I have already told her about it.“You shall have my answer tomorrow.你明天可以得到我的答复。（说话人的允诺）I should write some letters tonight.今晚我得写几封信。（表“应当”，）They should be there by now.他
10、们现在可能到了。（推测）Tom advises/suggests John that he should go to school by bus.(给建议)当我是个学生的时候，我总是10点钟睡觉 When I was a student，I go to bed at 10：00 in the evening.表示动作过去反复发生，would 小明问妈妈他可以看电视吗 -“Mom，I watch TV？”Might/could/may/can I do sth?我可以做某事吗？Yes,you may/can.No,you may not/cant mustnt.适用语境:下级向上级申请许可.小明
11、做完作业，问妈妈他可以看电视吗.妈妈也拿不定主意,就问小明他爸 -“I let him watch TV?”Shall I/we/he/she/they do sth?Will you do sth?某人做某事好吗？适用语境:平等关系的人之间询问意见.小明问妈妈他可以看电视吗.妈妈也拿不定主意,就问小明他爸.爸爸就问小明是否已完成作业,小明不说话.爸爸就说 -“you finish your homework first”sb should do sth 某人应该做某事.适用语境:给建议 sb must do sth 某人必须做某事 适用语境:给命令(肯定句,疑问句)sb neednt do
12、sth,sb doesnt have to do sth.某人不必做某事(否定句)小明请姐姐帮忙做作业,姐姐提出要小明帮她做 一 个 星 期 的 家 务 来 交 换.小 明 说 I rather do it myself.sb.would rather do sth.某人宁可做某事 小时候无法实现的愿望,以为长大后就能实现.然而到现在还是不能实现,不过我仍相信,有一天梦想总能实现.When I was a child,I had a dream that I not fulfill.I thought I be able to fulfill it when I grew up.However
13、,I still not.But I still believe that I be able to make dream come true one day.答案:could,would,can,will 现在时can-过去时 could 现在将来时 will be able to-过去将来时 would be able to小明有一天放学了还没回家,妈妈有点担心,对爸爸说 “it is already 6:00,Xiao Ming be here.I am worried about him.”sb.should do sth.某人应该做某事 适用语境:根据以往经验做出的合理推测 爸爸安慰
14、妈妈说 “he play with his friends,and forgets to go home.”Sb might/may/could do sth 某人可能做某事.适用语境：不太肯定的猜测小明上课在睡觉,老师没有叫他起来.老师解释说“He be ill.He looks so pale.”sb must do sth/sb must be doing sth/sb must be+adj.某人现在肯定怎样 适用语境:非常肯定的猜测(肯定句)(否定句,疑问句)cant/couldnt can could 注:can,could 有时也用于肯定句,意为”有时候是”新年小明下决心道:”I study hard.”sb will/would do sth 某人要做某事 (表意愿,承诺等)homework 完成课本P5 2 P43 using structures 1，2
