1、情态动词命题特征：1,情态动词的用法和辨析have to/must neednt/mustnt can/may cant/mustnt2,情态动词表示推测，可能cant must may could can should 3，情态动词引出的一般疑问句的回答Must I.No，you.情态动词：情态动词：表示说话人对某一动作或状态的态度，认为表示说话人对某一动作或状态的态度，认为“可能可能”、“应当应当”、“必要必要”等等。等等。必须和动词原形连用。必须和动词原形连用。情态动词没有人称和数的变化。情态动词没有人称和数的变化。can and could may and might will and
2、 would shall and should must and cant 只做情态动词：must，can（could），may（might）既可做情态动词又可做实意动词：need具有情态动词的某些特征：have to be able toought to情态动词的特征：有一定的词义但不能单独做谓语 必须和行为动词或系动词连用，构成谓语无人称、数的变化（have to 除外）1，can 和could的用法(1)表示能力，意为“会，能”I can play basketball.(2)表示怀疑，否定的推测，常用于否定句中Li Hua cant be in the classroom.李华不可能在
3、教室。(3)表示请求或允许，“可以”多用于口语You can go now.(4)could 是can 的过去时，可以表示过去 的能力I could swim when I was 5 years old.-Listen!Is Professor Johnson giving a report in the hall?-No,it _ be him.He has gone to Japan.A.needntB.may not C.mustnt D.cantD It is usually warm in my hometown in March,but it _ be rather cold s
4、ometimes.A.must B.can C.should D.would B以can 开头的一般疑问句：肯定回答：can 否定回答：cant以could 开头的一般疑问句：肯定回答：could 否定回答：couldntCould you skate last year？yes，I could.No，I couldnt-Can you ride a horse?-No,I _.A.neednt B.may not C.cant D.mustntCWhose T-shirt is this？It_be Jones.It is _small for him.A.cant;much too B.c
5、ant;too much C.mustnt;much too D.mustnt;too muchAcant ,mustnt 表示否定推测时用：cant mustnt:禁止，不允许 不能用来推测 must 在肯定句中表示推测，意为“一定”may 与might1.表示表示“许可许可”或或“请求请求”，有，有“可以可以”的意思，的意思，。比。比can正式。正式。口语中常用口语中常用 might 代代 may,表示委婉语气表示委婉语气 否定回答时常用否定回答时常用“must not”表表“禁止，阻止禁止，阻止”1)-May/Might I watch TV after supper?-Yes,you
6、may./Yes,please.(No,you mustnt.)2.表示可能性。意为“或许，可能”常用于肯定句或否定句中。might 比 may 可能性小。（1）他们现在可能在图书馆。They may/might be in the library now.（2）她可能已经回家了。She may/might have gone home.-Is that our new English teacher?-Well,it_be,but I am not quite sure.A.should B.might C.must D.cantB3.May you+动词原形动词原形 表表“希望、祝愿希望、
7、祝愿”May you have a good journey!May all your dreams come true！must（1）表示“必须，应该”（2）表示推测：”一定“（一般用于肯定句）He must be in the classroom.There is someone knocking at the door.It must be Jim.（3）否定句中，mustnt表示”禁止“You mustnt take photo here.Susan has bought a large house with a swimming pool.-It _ be very expensiv
8、e.I never even dream about it.A.must B.might C.cant D.shouldnt AAnother cup of coffee?-No,thanks.I _ be off.Mary is waiting for me.A.can B.may C.must D.mightC以must开头的疑问句肯定回答用:must 否定回答用:neednt，表示不需要，不必。相当于:do not have to -Must I finish the project today?我必须今天完成这个项目吗？-No,you neednt.不，你不必。Must I finis
9、h watering the flowers now?-No,you_.A.must B.wont C.neednt D.cantC If the traffic light is red,you _ cross the road.Its dangerous.A.dont B.neednt C.mustnt D.wouldntC4，need的用法：need to do 实意动词need doing被动need do情态动词词性的判断-Im a little tired.Lets go to the zoo by taxi.-We _ take a taxi.Its not far from h
10、ere.A.cant B.mustnt C.couldnt D.needntDshall（should）（1）shall 用于第一、三人称表示征求意见，询问 Shall I open the window？Shall we go now？（2）should 常表示义务、责任 We should obey traffic laws.1)Its 8 oclock now,he should be here at this moment.2)Dinner should be ready by now.表示可能性、推测、推论或期待表示可能性、推测、推论或期待,意为意为“可能、可能、按理说、该按理说、该
11、”will/wouldwill：第二人称表示请求，询问Will you pass me the book？也表达现在的意愿We will do everything for you.would would 表示过去的意愿或委婉的询问Would you tell me the way to the station?比较：can 和be able to表示能力时用法相同，一般现在时一般过去时be able to 有三种时态Jim couldt speak Chinese last year,but now he can.We will be able to come back next week.canmust 和have to同：“必须”异：have to:强调客观需求“不得不”must:强调主观，“必须”We must work hard at school.It is 9 oclock,I have to go.
