状语从句

本节导读

状语从句在句子里作状语，说明动作发生的时间、地点、原因、条件、目的、结果等。词汇与语法部分常考连接词的选择，也就是在空格里选 because、although、unless、so that 这一类词，还会考 so…that 与 such…that 的区别。

学完这一节，你应该能说出各类状语从句的常用连接词，避免 because 与 so 同时使用这类错误，并能熟练区分 so 与 such。

状语从句的类型和连接词

类型	常用连接词	例句
时间	when, while, as, before, after, since, until, as soon as, once	I will call you as soon as I arrive.
地点	where, wherever	Sit wherever you like.
原因	because, since, as, now that	He didn't come because he was ill.
目的	so that, in order that, lest	He spoke slowly so that everyone could understand.

类型	常用连接词	例句
结果	so…that, such…that	It was so cold that we stayed at home.
条件	if, unless, as long as, in case, provided that	You will fail unless you work harder.
让步	though, although, even if, even though, while	Although he was tired, he kept working.
比较	than, as…as	He runs faster than I do.
方式	as, as if, as though	Do as I told you.

时间状语从句

• when 表示「当……时」，动作可长可短；while 强调一段时间内的动作，从句多用进行时；as 可表示「一边……一边……」「随着」。
• since 表示「自从」，主句用现在完成时，从句用一般过去时：I have lived here since I was born.
• not…until… 表示「直到……才……」：He did not go to bed until he had finished his homework.
• by the time 后面的从句用一般过去时，主句常用过去完成时：By the time we arrived, the film had begun.
• hardly…when… 和 no sooner…than… 表示「一……就……」，前一部分用过去完成时，后一部分用一般过去时。

时间、条件状语从句里，主句是将来时，从句要用一般现在时：I will tell him when he comes back.

原因、条件和让步

because 表示直接的原因，回答 why 的问题；since 和 as 表示显而易见的、已知的原因，通常放在句首。

三个常考的逻辑搭配要记住：

要点	例句
because 不与 so 连用	Because it rained, we stayed at home. 或 It rained, so we stayed at home.
although/though 不与 but 连用	Although he is poor, he is happy.
unless 相当于 if…not	Unless you hurry, you will be late. 相当于 If you don't hurry, you will be late.

in case 的意思是「以防万一」：Take an umbrella in case it rains. 注意 although 与 yet 或 still 可以同时用：Although he is poor, he is still happy.

让步状语从句还可以用 whatever、however、whoever 引导，意思是「无论什么、无论如何、无论谁」，如 Whatever you say, I won't change my mind.