2009年12月大学英语四六级考试语法精要(六)

　　Ⅱ 状语从句

　　1. 状语从句中以下四种从句考得较多，这里给予简单介绍。

　　1) 时间状语从句

　　时间状语从句主要由以下连词引导：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.

　　时间状语从句还可由某些可充当连词的名词(the moment, the instant, every time,等)和副词(instantly, directly等)引导：

　　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，还可用来强调主句所表达的时间、距离很长或花费的力量相比较大，可译为“…才”。(“not … before” 可用来强调主句所表达的时间、距离很短或花费的力量相比较小，可译为“…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引导的分句之前的主句使用过去进行时、过去完成时或“was/were about to, was/were on the point of”等结构时，when表示突然发生某事，可译为“正在…突然”或“刚…就”等。这时，不能够用as或while来代替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) 条件状语从句

　　条件状语从句主要由以下连词引导：if, unless, providing/provided (that), suppose/supposing (that), on condition (that), as/so long as, in case等。