部分情态动词的用法.doc

情态动词shall ,will ,should和would的用法情态动词shall ,will ,should和would 在不同的句子中含有不同的意思，其基本用法如下：一、shall1. 表示说话者的意图、允许、警告、命令、决心等，用于陈述句的第二、第三人称中，有必须，应，可之意。例如：）You shall have that book tomorrow.2) He shall be punished if he insists on doing that.2,. 在问句中表示征求对方意见，主要用于第一、第三人称，有“.好吗”，“要不要”等意思。例如“1) Shall I fetch the hammer?2) Shall those goods be sent over to you at once?3) Shall we help you?2. 用在表示意图、要求等的从句中，有“应该”，“要”之意，例如：My demand is that is shall be done in time.二、should 1.表示义务、责任、建议或劝告，有“应当、应该”的意思。例如：1) You should learn from each other.2) You shouldnt be so careless.3) He should have told me the news earlier.(should + have + 过去分词)表示对过去本该做的事而没有做，其否定形式是对过去本不做的事而做了的固定句型。与why ,who ,how等词连用，表示意外、惊异等，有“竟会”等意思。例如：1) How should I know?2) Why should you be so late today?用于表示建议、命令、决定等的从句中，有“应该、必须”的意思。例如：1) The young doctor proposed that he should try the experiment on himself.2) It was decided that we should start a cleanup at once.。表示可能性、推测或推论，有“可能、该”等意思。例如：They should have arrived in Beijing by this time.用于虚拟语气句子中，有“万一、竟然、就、该”等意思。例如：1) Should it rain tomorrow (或If it should rain tomorrow ) ,the meeting would be postponed.2) If the book were in the library ,you should have it. (should 在句子里表说话人的意愿)三、will 表示意志、意愿，有“愿、要”之意。例如：1) We will fight on until final victory is won.2) I will do my best to help you.3) She will not shove the heavy load on to others.在疑问句中用于第二人称，表示说话人向对方提出请求或询问对方的意思，有“你.好吗、你愿.”。例如：1) Will you help me with my work?2) Will you join our discussion?表示习惯、经常性、倾向性，有“惯于、总是”等意义。例如：Every morning he will have a walk along this river.在if ,when ,until等连词引导的表示时间或条件的从句中要用一般时表将来，但在if 从句中有时为了表示意愿也可用will ，有“愿意”的意思。例如：1) If you will read this article ,you will realize you are wrong.2) If they wont help us ,we can not finish the task within one month.四、wouldWill 的过去式，表示对过去时间的意志、意愿、决心，有“愿、要、偏要”的意思。例如：1) I promised that I would do my best.2) I told him not to go ,but he would not listen to me.表示请求或个人的想法、看法，使语气婉转，有“愿、倒”等意思，例如：1) Would you please take a seat?2) Would you mind opening the window?3) I would like to express my thanks to you.表示过去习惯性的动作，着重动作的重复，有“总是、总会”等意思。例如：On Sundays he would come to our village and work with us.表示虚拟、假设、条件等，有“要、将要、会、就会”等意思。例如：1) If you had come earlier ,you would have seen him.2) It would be better to adopt the new method.示例考题It is nearly seven ,Jack _ be here at any moment. (NMET1995)A. must B. Need C. Should D. can解析这是带与语境的句子，从第一句的句意，我们便可以了解到第二句属推测句型，这样可排除选项，在推测句型中否定句和疑问句中，故选为正确，should 表示可能性的推测。