2015职称英语重点语法解析之让步状语及时间状语

　　职称英语重点语法解析之让步状语及时间状语

　　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。

　　让步状语从句

　　although与though可以引导让步状语从句，不能与but连用，但可以与yet连用。

　　Although they are poor,they are warm-hearted.

　　even if或even though引导让步状语从句，表示即使，纵然，用来使人注意下文所强调内容的性质。

　　Ill get there even ifI have to sell my house to get enough money to go by air.

　　no matter后接上who、what、where、how等疑问词，也可以在这类疑问词后面加上ever构成whoever、whatever、wherever、however等。

　　Dont trust him, no matter what / whatever he says.

　　Whoever breaks the law will be published.

　　No matter how hard the work is, youd better try to do it well.

　　as也可以引导让步状语从句，要用倒装。

　　Child ashe is, he knows a lot.

　　Much as I like it, I wont buy.

　　Try as he would, he couldnt lift the heavy box.

　　时间状语从句

　　as、when、while

　　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.

　　The runners started as the gun went off.

　　when：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.

　　When we were at school, we went to the library every day.

　　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 dont talk so loud while others are working.

　　He fell asleep while/when reading. Strike while the iron is hot.

　　引导时间状语从句的连接词除上述外还有：

　　①till、notuntil、until、before、since

　　Dont get off the bus until it has stopped.

　　He waited for his father untilit was twelve oclock.

　　It will be five years before he returns from England.