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。精品学习网特分享常考的英语状语从句，供大家阅读!

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……”。