Ifthenewsafetysystem

問題詳情：

If the new safety system _______ to use, the accident would never have happened.

A．had been put        B．were put               C．should be put      D．would be put

【回答】

A

 【詳解】

考查虛擬語氣。句意：如果這個新的安全系統被投入使用過的話，這個事故就不會發生了。根據主句確定是對過去情況的虛擬，所以從句謂語用had done形式，此外根據句意可知是被動，用被動語態，故A項是正確的。

【點睛】

英語中的三種語氣，語氣是動詞的一種形式，用來説明我們對自己的話所採取的態度。陳述語氣（疑問，否定，肯定，感歎）祈使語氣（命令，要求，建議，*告）虛擬語氣：不可能發生的事，願望，建議，與事實相反的假設等.虛擬語氣在條件中的具體用法真實條件句If you work hard,you’ll surely pass the exam.虛擬條件句（假設情況不存在，實現機會很小）If I were a bird, I could fly freely in the 從句的謂語動詞主句謂語動詞1.與現在事實相反動詞過去式（be一律用were）would/could/might/should+動詞原形2.與過去事實相反had donewould/could/might/should+have done3.與將來事實可能相反a.動詞過去式（be一律用were）ld+動詞原形（不能用would） to+動詞原形would/could/might/should+動詞原形與現在事實相反if從句：動詞過去式（be---were）主句：would/could/might/should+動詞原形If we had time, we would go with I were you, I shouldn’t do it weren’t raining, we wouldn’t stay.與過去事實相反if從句：had done主句：would/could/might/should+have doneIf the teacher hadn’t helped us, we couldn’t have succeeded.I could have done it better if I had been more he hadn’t been ill, he might have come.3.與將來事實可能相反if從句：a.動詞過去式（be一律用were）        ld+動詞原形（不能用would）        to+動詞原形主句：would/could/might/should+動詞原形If he came tomorrow, I would tell him it should rain tomorrow, I would stay at home and watch it were to snow tomorrow, they would not go ld he come tomorrow, please give the book to him.錯綜時間條件句在虛擬語氣中，有時條件從句動作發生的時間和主句動作發生的時間是不一致的，稱為錯綜時間條件句。這種句子的形式往往要根據句子的時間相調整，分別處理。If you had spoken to him yesterday, you would know what to do you had followed the doctor’s advice then, you would be all right you had watered them more, the crops would be growing still better now.(有時時間會省略）含蓄條件句有時虛擬條件不用if條件從句，而用介詞或介詞短語來表示。They would not be able to live without him.（如果沒有）He would have failed but for his teacher’s timely advice.（要不是）=if it had not been forIf only you had worked with greater care!(要是......就好了）You would have done the same thing in her a little more care you could have avoid the traffic accident.虛擬結合條件句在虛擬語氣中，假設的情況有時間可以通過上下文或其他方式表現出來，並且虛擬的情況和真實的情況同時存在。I was ill that day. Otherwise, I would have taken part in the singing competition.（實------虛）=I was ill that day. If I hadn’t been ill that day, I would have taken part in the singing would have bought the piano, but he didn’t have enough money.（虛------實）=He would have bought the piano if he had had enough money, but in fact he didn’t have enough money.省略if倒裝條件句在虛擬語氣中，if從句假設的情況中如果有助動詞had, should和were，那麼可省略if，把had, should和were放在句首構成倒裝，簡稱省略if倒裝條件句。If he had finished the work yesterday, he would have gone to the concert with you.=Had he finished the work yesterday, he would have gone to the concert with I were you, I wouldn’t do that.=were I you, I wouldn’t do I should meet him, I would tell him about it.=Should I meet him, I would tell him about it.

知識點：過去完成時及其被動式

題型：選擇題