虛擬語氣2

　　虛擬語氣(Subjunctive Mood)這一語法項目是各類英語考試中心測試的重點之一。虛擬語氣是一種特殊的動詞形式，用來表示說話人所說的話并不是事實，而是一種假設、愿望、懷疑或推測。判斷是真實條件句還是非真實條件句。只有在非真實條件句中才使用虛擬語氣。通過句子意思，看假設的條件是否能夠實現，能夠實現是真實條件句，不能使用虛擬語氣；假設的條件不能實現則是非真實條件句，要用虛擬語氣.判斷這個假設是與哪個事實相反。通常有三種情況：①與過去事實相反。②與現在事實相反。③與將來事實可能相反

　　I: 最基本的虛擬語氣句型:

　　1. 虛擬現在時表示與現在事實相反的假設，其if 從句的謂語形式用動詞的過去式(be 一般用were)，主句用would/ should/ could/ might +動詞原形。If places were a like, there would be little need for geographers.如果各個地方都一樣，就不需要地理學家了。

　　2. 虛擬過去時是表示與過去事實相反的假設，if 從句的謂語形式用過去完成時即had＋過去分詞，主句用would / should / could / might + have +過去分詞。If he had known your address yesterday,he would have telephoned you.

　　3. 虛擬將來時是表示對將來實現的可能性很小的或不確定的假設。If從句的謂語形式用一般過去式或用were to / should +動詞原形，主句用would / should/could/ might +動詞原形。If he were to leave today, he would get there by Friday

　　4. 省略if 采用倒裝語序的條件句。有時可以把含有助動詞、情態動詞、be或have的虛擬條件句中的連詞if省去，而將had , should, were 等詞提到主語之前，即用倒裝結構。Had he worked harder, he would have got through the exams.Were he to leave today, he would get there by Friday.Were I in your place, I wouldn’t do that.

　　5. 有時虛擬條件句并沒來if 從句表示出來，而是用介詞短語(otherwise, or, without, but for)、上下文或其它方式來表示。We didn't know his telephone number; otherwise we would have telephoned him.Without you help, I wouldn’t have achieved so much.But for your help, I would not have succeeded. 

　　II: 虛擬語氣在從句中用should的情況:

　　1. 在建議,要求,命令,想法后的動詞后的從句里, 用should + 動詞原形, should 可以省略. 如 advise, agree, command, decide, demand, determine, grant, indicate, insist, order, prefer, propose, request, require, stipulate, suggest, urge, vote.常考到的是: suggest, advise, demand, require, propose, insist, order, request.

　　His doctor suggested that he (should) take short leave of absence.

　　The author proposed that TV (should) be turned off at least one hour every day.

　　2. 在建議,要求,命令,想法后的名詞后的從句里, 用should + 動詞原形, should可以省略. 如 advice, agreement, command, decision, decree, demand, determination, indication, insistence, order, preference, proposal, request, requirement, stipulation etc.

　　It was Bill’s suggestion that everyone (should) have a map.

　　His suggestion was that everyone (should) have a map.

　　He gave us a suggestion that everyone (should) have a map.

　　3. 在It is/was +形容詞后的that 從句中用should的結構, should 可以省略. 這類形容詞常見的有: advisable, anxious, compulsory, crucial, desirable, eager, essential, fitting, imperative(絕對必要), impossible, improper, important, natural, necessary, obligatory, possible, preferable, probable, recommended, urgent, vital etc.

　　It‘s natural that she (should) do so.

　　It is essential that we (should) tell her the news.

　　4. 在 lest 和 for fear that(以免),in case(以防)從句中用should, should 可以省略.

　　She walked quietly lest she (should) wake up her roommates.

　　Have your gun ready in case we should need it. 

　　III: wish 后的 that 從句中:

　　1. 表示現在或將來的愿望,從句中過去式.

　　I wish I knew his address.

　　I wish I were young.

　　2. 表示過去沒有實現或不可能實現的愿望, 從句用過去完成式或would, could, might + have + 過去分詞.

　　I wish you had written to him.

　　I wish I could have slept longer this morning, but I had to get up and come to class.

　　3. 如果將wish改成wished, 其后that 從句中的動詞形式不變.

　　4. 如果that 從句中用would , 一般表示 對現狀不滿或希望未來有所改變或請求

　　I wish he would answer my letter.

　　I wish prices would come down.

　　I wish you would help me.

　　I wish you would stop asking silly questions.

　　IV: 在 It’s about/ high/ first(second, third etc)time 后的that 從句中,用過去式.表示“該是做什么的時候了”

　　It is about time you were in bed.

　　It is high time we left.

　　It is the first time I came here.

　　V: 在would rather, would sooner, would just as soon 后的that從句中,用過去式或過去完成式,表示”寧愿做什么”

　　I would rather he came tomorrow than today.

　　John would rather that she had not gone to the party yesterday evening. 

　　VI: 在if only 感嘆句中,謂語動詞與wish賓語從句的虛擬形式相同.

　　If only he didn’t drive so fast!(現在)

　　If only she had asked someone’s advice.(過去)

　　If only the rain would stop.(將來)

　　VII: 在as if / as though 從句中,表示和現在事實相反或對現在情況有所懷疑,用過去式;表示過去想象中的動作或情況, 用過去完成式.

　　He speaks as if he were on the spot.

　　She spoke to me as if I were deaf.

　　This device operated as though it had been repaired.

　　注: 1. 在 as if / as though 句中, 如果有可能成為事實, 用陳述語氣.

　　He looks as if he is going to be ill.

　　2. 在 insist 后的從句中, 如果是堅持自己, 用陳述語氣, 堅持別人做什么事情, 用虛擬語氣.

　　She insists that she is right.

　　She insisted that I should finish the work at once.