牛津上海版7A状语从句专项讲解及练习（有答案）

状语从句 一、基本概念 状语从句指的是在主从复合句中作状语的从句，修饰主句中的动词、形容词或副词等。状语从句由从属连词引导。状语从句放在主句之前时，常用逗号分开；若放在主句之后，一般不用逗号。 二、基本分类 1.时间状语从句：When Susan goes to town, she will visit her grandma. 2.条件状语从句：If he works hard, he will surely succeed.按意义和作用 3.结果状语从句：Waste must be treated so that it does not become a danger to life. 4.目的状语从句：They worked hard in order that they might succeed. 5.原因状语从句：Mary didn't go shopping because I advised her not to. 6.让步状语从句：Though we are all different, we need never be separate. 7.比较状语从句：I was happier than I had ever been in my life. 8.地点状语从句：I will go where I am needed. 9.方式状语从句：I have changed it as you suggest. 三、用法详解 时间状语从句 when , while, as , after, before, since, as soon as ,till (until), not…until… , … 1）引导词： 2）辨析： ※until，till用于肯定句时，表示“直到……为止”，主句必须为持续性动词。 We shall wait until/till he comes back. Everything went well until/till that accident happened. ※not…until/till表示“直到……才……”，主句通常要用短暂动词，这时until和till可用before代替。 I d