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      1. 酷兔英語

        章節正文

            情態動詞 (Model Verbs) 又稱為情態助動詞 (Model Auxil-iaries)。英語中助動詞主要有兩類:一是基本助動詞,如have, do, be;二是情態助動詞,如may, must, need等。情態動詞與其他動詞連用表示說話人的語氣。情態動詞可表達建議、要求、可能和意愿等。情態動詞沒有人稱和數的變化。在大學英語四、六級考試中,情態動詞部分重點測試以下內容:

            1)情態動詞+行為動詞完成式

            2)情態動詞+行為動詞進行式

            3)情態動詞+行為動詞完成進行式

            4)某些情態動詞的特殊用法

            一、情態動詞+行為動詞完成式

            情態動詞+行為動詞完成式即“情態動詞+ have + v-ed分詞”,表示對過去行為或動作進行推測、評論或判斷。

            1. must have v-ed

            must have v-ed 表示推測過去某事“一定”發生了。其否定形式為:cant / couldnt have v-ed, 表示過去不可能發生某事。例如:

            1Since the ditch is full of water, it must have rained last night.

            2You couldnt have met my grandmother. She died before you were born.

            2. could have v-ed

            could have v-ed 表示推測過去某動作“很可能”發生了。例如:

            1The dictionary has disappeared. Who could have taken it?

            2Tom could have taken it. He was alone yesterday.

            3.may / might have v-ed

            may / might have v-ed 表示推測過去某事“也許”發生了.may might 表示的可能性在說話人看來稍大些。例如:

            I cant find my keys. I may / might have left them at the school yesterday.

            4. ought to / should have v-ed ought not to / shouldnt have v-ed

            ought to / should have v-ed ought not to / shouldnt have v-ed 用于對已發生的情況表示“責備”、“不滿”,分別表示“本應該…”和“本不應該…”。例如:

            1With all the work finished, I should have gone to the party last night.

            2You ought not to make fun of him. He is not the one you laugh at but learn from.

            5. neednt have v-ed

            neednt have v-ed 表示過去做了某事,但沒有做的必要, 意為“本沒必要…”。例如:

            You neednt have waken me up; I dont have to go to work today.

            注:表示推測過去某動作發生的可能性時,就表示的可能性程度而言,must最大,could其次,may更次之,might最小。例如:

            I wonder how Tom knew about your past.

            He must / could / may / might have heard of it from Mary.

            二、情態動詞+行為動詞進行式

            情態動詞+行為動詞進行式(即情態動詞+ be + v-ing形式),表示推測或評論某動作現在是否正在進行。例如:

            1He must be playing basketball in the room.

            2She may be staying at home.

            三、情態動詞+行為動詞完成進行式

            情態動詞+行為動詞完成進行式(即情態動詞+ have been + v-ing 形式),表示推測或評論過去某動作是否正在進行或一直在進行。例如:

            1They should have been meeting to discuss the problem.

            2He may / might have been buying stamps in the post office when you saw him.

            四、某些情態動詞的特殊用法

            1. need

            考試中主要測試 need 作情態動詞與作實義動詞的區別,對此,可參見表1.need 作情態動詞時,后面跟不帶to 的動詞不定式,即 need to。通常用在疑問句和否定句中,表示詢問是否有“必要”,其否定形式為neednt,表示“不必”;疑問形式為 Need do? 極少用于肯定句。例如:

            1I dont think we need turn the light on at that time.

            2Need you ride a bike to school?

            情態動詞need與實義動詞need 在時態、肯定、否定結構上的對比見表1

            2. dare

            考試中主要測試dare作情態動詞和作實義動詞的區別。

            情態動詞dare 與實義動詞dare 在時態、肯定、否定、疑問結構上的對比見表2

            3. can may

        考試中主要測試canmaycouldmight表示可能性的區別及對may構成的疑問句的回答。

         

        時態      情態動詞need               實義動詞 need

              You need (not) do      You (dont) need to do           

             

              He need (not) do       He needs (doesnt need) to do

         

                                     You needed (didnt need) to do 

            

                                     He needed (didnt need) to do

         

             You need (not) do       You will (not) need to do

         

             He need (not) do        He will (not) need to do

         

         

         

         

         句型    時態                     動詞  

                          情態動詞dare           實義動詞 dare

        肯定句  現在時  dare to 少用           dare/dares to do

                過去時  dare to 少用           dared to do

        否定句  現在時  darent/dare not do    do/does not dare (to) do 

                過去時  dared not do           did not dare (to) do

        疑問句  現在時  Dare he do?             Do you/Does he dear (to) do?

                過去時  Dared he do?           Did he dare (to) do

            1can, could, may, might都可以表示可能性.can, could表示潛在的可能性或理論上或邏輯判斷上存在的可能性;而may, might則表示事實上的可能性。此外,can還具有“有能力”的意思,而maymight則不具此意。例如:

            1According to the weather forecast, it may rain tomorrow.

            2) Any man with a little sense can see that he is wrong.

           2May I / we …?這一類疑問句的肯定回答為Yes, please.Certainly;否定回答為Please dont.No, you mustnt. 例如:

            May we leave now?No, you mustnt. You havent finished your home work yet.

            4. can be able to

            can be able to 都可以表示能力,但兩者在用法上有點差異:can (could)表示主觀能力,不表示意愿,它的將來時用will be able to; be able to表示主觀意愿,強調要克服困難去做某事。例如:

            1My grandma is over seventy, but she can still read without glasses.

            2He is able to give up his bad habits.

            5. must have to

            must have to 都可以表示“必須”,但有幾點區別:

           1must 強調“內在的職責”、“義務”,而have to 強調“外界壓力”、“不得已而為之”。

           2have to可用于多種時態,而must一般用于現在時,其過去時與將來時分別由had toshall / will have to代替。

           3)在回答must引起的問題時,如果是否定的答復,不能用mustnt,而要用needntdont have to,因為mustnt是“一定不要”、“一定不能”的意思。例如:

            1You must come to the classroom before eight.

            2It is raining hard outside, but I have to leave now.

            3Must we do it now?No, you neednt.

            6. used to +v, be used to +v-ingbe used to +v

           1used to +v意為“過去常常”,“過去一直”;be used to +v-ing / n(名詞)意為“習慣于”;be used to +v意為“被用來(做某事)”。

           2used to只表示過去,而be used to +v-ing / n可表示現在、過去或將來。例如:

            1He used to smoke. Now he doesnt.

            2Hes quite used to hard work / working hard.

            3The knife is used to cut bread.

            7.用作情態動詞的其他短語

            would rather, would sooner, would (just) as soon, had rather, had better, had sooner, can not but, may (just) as well等可用作情態動詞。例如:

            1The soldier would sooner die than surrender.

            2The brave soldier would as soon die as yield to such an enemy.

            3Id rather walk than take a bus.

            4If you dont like to swim, you may just as well stay at home.

            注:這些短語后一般直接跟動詞原形.would (had) rather, would (had) sooner, would (just) as soon后可跟that 引導的從句,that 常省去,從句要用虛擬語氣。對現在和將來的假設用過去時,對過去的假設用過去完成時。例如:

            1I would rather you came on Sunday.

         

            2I would sooner you hadnt asked me to speak yesterday.


        生詞表:
      2. grandmother [´gr?n,m?e?] 移動到這兒單詞發聲  n.(外)祖母   (初中英語單詞)
      3. working [´w?:ki?] 移動到這兒單詞發聲  a.工人的;勞動的   (初中英語單詞)
      4. yesterday [´jest?di] 移動到這兒單詞發聲  n.&ad.昨天;前不久   (初中英語單詞)
      5. grandma [´gr?nmɑ:] 移動到這兒單詞發聲  n.奶奶;外婆   (高中英語單詞)
      6. forecast [´f?:kɑ:st] 移動到這兒單詞發聲  vt.&n.預測;預報   (英語六級單詞)



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