2009年12月大學英語四六級考試語法精要(六)

　　Ⅱ 狀語從句

　　1. 狀語從句中以下四種從句考得較多，這里給予簡單介紹。

　　1) 時間狀語從句

　　時間狀語從句主要由以下連詞引導：when, whenever, as, while, since, until, till, before, after, as soon as, once, hardly (scarcely) … when, no sooner … than。

　　I will discuss the matter with you when we meet tomorrow.

　　He didn’t go to sleep until he finished doing his homework.

　　You have changed a lot since we met last time.

　　時間狀語從句還可由某些可充當連詞的名詞(the moment, the instant, every time,等)和副詞(instantly, directly等)引導：

　　I will tell you the news the instant I know.

　　Directly the teacher came in everyone was quiet.

　　Note:

　　① before除了可表示 “在…之前”外，還可用來強調(diào)主句所表達的時間、距離很長或花費的力量相比較大，可譯為“…才”。(“not … before” 可用來強調(diào)主句所表達的時間、距離很短或花費的力量相比較小，可譯為“…就”)。

　　It was a long time before I got to sleep again.

　　They had not been married a month before they quarreled.

　　② 如果位于when引導的分句之前的主句使用過去進行時、過去完成時或“was/were about to, was/were on the point of”等結(jié)構(gòu)時，when表示突然發(fā)生某事，可譯為“正在…突然”或“剛…就”等。這時，不能夠用as或while來代替when。

　　I was walking on the street when I ran into my old friend John.

　　She had just fallen asleep when the telephone rang.

　　We were about to leave when it began to rain.

　　2) 條件狀語從句

　　條件狀語從句主要由以下連詞引導：if, unless, providing/provided (that), suppose/supposing (that), on condition (that), as/so long as, in case等。