职称英语考试语法指导：状语从句1

职称英语考试语法指导：状语从句1

状语从句指句子用作状语时，起副词作用的句子。它可以修饰谓语、非谓语动词、定语、状语或整个句子。根据其作用可分为时间、地点、原因、条件、目的、结果、让步、方式和比较等从句。状语从句一般由连词(从属连词)引导，也可以由词组引起。从句位于句首或句中时通常用逗号与主句隔开，位于句尾时可以不用逗号隔开。

时间状语从句(1)as、when、while用法as表示“当……的时候”，往往和when/ while通用，但它着重强调主句与从句的动作或事情同时或几乎同时发生。She came up as I was cooking.(同时)The runners started as the gun went off.(几乎同时)

　　when:(at or during the time that )既可以表示在某一点的时候，又可表示在某一段时间内，主句与从句的动作或事情可以同时发生也可以先后发生。It was raining when we arrived.(指时间点)When we were at school, we went to the library every day.(在一段时间内)

　　while意思是“当……的时候”或“在某一段时间里”。主句中的动作或事情在从句中的动作或事情的进展过程中发生，从句中的动词一般要用延续性动词。在when表示a period of time时，两者可以互换。Please don’t talk so loud while others are working.He fell asleep while/when reading. Strike while the iron is hot.(用as或when不可，这里的while意思是“趁……”)

　　(2)引导时间状语从句的连接词除上述外还有：①till, not …　until …, until, before, sinceDon’t get off the bus until it has stopped.He waited for his father until(till)it was twelve o’clock.It will be five years before he returns from England.

　　②hardly / scarcely … when, no sooner … than, as soon as once表示“一……就”As soon as I have finished it , I’ll give yu a call.Once you show any fear, he will attack you.We had hardly got / Hardly had we got into the country when itbegan to rain.No sooner had he arrived / He had no sooner arrived than she started complaining.

　　③directly, immediately, the moment, the minute that… 一……就He made for the door directly he heard the knock.

　　④each time, every time, by the timeEach time he came to my city, he would call on me.注意：表示未来情况，主句用将来时，从句用现在时。