英語語法基礎(chǔ)-第3講(虛擬語氣).ppt

英語語法基礎(chǔ),第三講 虛擬語氣,一、語氣的種類,語氣和時態(tài)、語態(tài)一樣，也是關(guān)于動詞的一個語法范疇。英語中一共有三種語氣： 陳述語氣 敘述事實(shí)或是對真實(shí)情況提出問題。陳述句和疑問句大都屬于此類。絕大多數(shù)情況下我們使用的句子都是陳述語氣 祈使語氣 說話人向?qū)Ψ教岢鲆?，下達(dá)命令，給出指示等的語氣。使用祈使語氣的句子就是祈使句。例： Come here, please. Dont speak now. Be quiet, children. Lets go together. 虛擬語氣,虛擬語氣,表示一種假設(shè)的情況（實(shí)際并不存在）或主觀愿望。虛擬語氣有時可以使說話人的語氣緩和、客氣、委婉。例： If I were you, I would accept this job. If you had come yesterday, you would have seen that famous basketball player. 虛擬語氣多用于含有條件句的主從復(fù)合句中。這種含有虛擬語氣的條件句稱為虛擬條件句。虛擬語氣也用于其他一些表示愿望、命令、好像等意思的結(jié)構(gòu)中。,二、虛擬語氣的構(gòu)成,A. 虛擬條件句的三種形式,二、虛擬語氣的構(gòu)成,例： What would you do about the problem if you were in my shoes? If I knew how the machine works, I would / should tell you what to do. If he had taken a little more time to think, he might have done it better. The patient is all right now. If he should be in danger again, we would/should send him to hospital at once.,二、虛擬語氣的構(gòu)成,注： 在表示與現(xiàn)在事實(shí)相反的假設(shè)時，現(xiàn)在的趨勢是在第一、三人稱單數(shù)主語后用was 代替were，但 “If I were you”在英國已成固定形式。 主句中的would可用于各種人稱，但是should只能用于第一人稱。 在主句中也可以用情態(tài)動詞could、 might代替would/should。,二、虛擬語氣的構(gòu)成,B. 錯綜時間條件句：在日常生活中，有時候條件句和主句所表示的動作不是在同一時間段內(nèi)，動詞的形式要根據(jù)句子表示的具體時間進(jìn)行調(diào)整，這樣的句子稱為錯綜時間條件句。 條件句與過去相反，主句與現(xiàn)在相反。例： If you had listened to the doctor, you would be well now. If you hadnt stayed up so late last night, you wouldnt be so sleepy now. 條件句與現(xiàn)在相反，主句與過去相反。例： You ought to have come last night, if you were really interested in Beijing opera. If it were not for the good policy, China would not have developed so fast. 注：If it were not for 這一句型表示“若不是”,二、虛擬語氣的構(gòu)成,C. 虛擬條件句中的if的省略：當(dāng)條件從句中含有were, had, should等詞時，就可以省略if，同時把were, had, should等詞置于句首（主謂倒裝）。例： If you had been here yesterday, you would have met her. Had you been here yesterday, you would have met her. If I were to solve this problem, I should do it in a different way. Were I to solve this problem, I should do it in a different way. If she should come, I would let you know at once. Should she come, I would let you know at once.,三、虛擬條件句的其他表示方法,有時，虛擬語氣不是用if條件句表示，而是用介詞短語或其他形式表達(dá)，但是，主句的表達(dá)仍然使用虛擬語氣，并根據(jù)動作發(fā)生的具體時間采用不同的形式。例： Without solar radiation, there would not be any living things on the earth. But for your help, I wouldnt have finished this job on time. I would have visited you then but I had been very busy.,四、有關(guān)虛擬語氣的一些句型,A. Its time 后面可以接三種結(jié)構(gòu)來表達(dá)同一個意思。例 ： Its time for supper. Its time for us to have our supper. Its time that we had supper. 注：這個句型表示“建議某人應(yīng)該做某事了”。 從句中的動詞必須用動詞的過去式。有時，為了突出強(qiáng)調(diào)時間，在time前面可以加上high或about，而譯成中文時則要省略。例： Its high time that we went to school. Its one oclock. Its about time that I were going to bed.,四、有關(guān)虛擬語氣的一些句型,B. wish后面的賓語從句：hope和wish都可以表示希望。但是兩個詞的意義有所差別 。 hope表示很有可能實(shí)現(xiàn)的愿望。例： He hopes that he will be a teacher when he grows up. wish表示一種幾乎無法實(shí)現(xiàn)的愿望，甚至是已經(jīng)不可挽回的現(xiàn)狀。例： I wish I could fly to the moon. wish后面的從句也可以用過去完成時，對已經(jīng)發(fā)生的事情表示遺憾、懊悔。例： She wishes she hadnt told him about it.,四、有關(guān)虛擬語氣的一些句型,C. would rather和had rather后面的從句：would rather和had rather表示“寧愿（做某事）”，在句子中起情態(tài)動詞的作用，后面跟動詞原形。但是，當(dāng)他們后面跟的是從句，從句的謂語動詞必須用虛擬語氣，即：動詞的過去式。例： I would rather stay here. I would rather you stayed here. I had rather go there at once. I had rather you went there at once.,四、有關(guān)虛擬語氣的一些句型,D. as if和as though后面的從句：一般用虛擬語氣。例： That old lady loves this boy as if he were her own son. He talked about New York as though he had been there himself. 注:在look, seem, taste, smell后，由as if 和as though引導(dǎo)的從句則用陳述語氣。例： It looks as if its going to snow. The milk smells as though it has turned sour.,四、有關(guān)虛擬語氣的一些句型,E. 在It is necessary等后面的主語從句中：從句的謂語動詞要用“should do”的形式，或是省略should保留動詞原形?？梢杂糜谶@種句型的形容詞有： appropriate 適當(dāng)?shù)?essential 絕對必要的 imperative 必須的 important 重要的 impossible 不可能的 natural 自然的 strange 陌生的 vital 極重要的 例： It is important that we (should) do morning exercises every day. It is natural that he (should) be late again.,四、有關(guān)虛擬語氣的一些句型,E. 在desire, demand, insist, order, recommend, require, suggest等表示命令、建議、要求的詞后面的從句中，用(should) + do的形式的虛擬語氣。例： He advised that we (should) go home right now. The teacher recommended that we (should) buy that reference book