状语从句是高考英语的必考考点，综观近年来各省市状语从句的考题情况，精品学习网的编辑为各位考生总结了历届高考英语常考的八种状语从句：

一、in case引导的状语从句

根据语境的不同，in case既可表示“如果”“万一”，引导条件状语从句;也可表示“以防(万一)”，引导目的状语从句。下面两道真题均选in case：

1. Leave your key with a neighbor ______ you lock yourself out one day. (北京卷)

A. ever since B. even if C. soon after D. in case

2. My parents live in a small village. They always keep candles in the house ______ there is a power cut. (重庆卷)

A. if B. unless C. in case D. so that

【解析】两道题都选in case，均表示“以防万一”。

二、before引导的状语从句

尤其要注意“it+be+一段时间+before…”这一句型。如：

1. The field research will take Joan and Paul about five months; it will be a long time ______ we meet them again. (安徽卷)

A. after B. before C. since D. when

2. He was told that it would be at least three more months ______ he could recover and return to work. (江西卷)

A. when B. before C. since D. that

【解析】两道题均before。第1题涉及的句式为：It will be a long time before…，意思是“要过很久才会……”;第2题涉及的句式为：it was some time before…，意思是“在……之前过了一段时间”，通常可转译为“要过一段时间才会……”。