状语从句(Adverbial Clause)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。英语状语从句用在主句后面的较多， 而汉语的状语从句用在主句前的较多， 因此， 在许多情况下， 应将状语从句放在主句前面。下面我们通过一些实例说明它们常用的翻译方法。
【真题例句1】
While there are almost as many definitions of historyas there are historians, modern practice most closely conforms to one that seeshistory as the attempt to recreate and explain the significant events of thepast。
【解析】
可拆分为：Whilethere are almost as many definitions of history //as there are historians, //modern practice most closely conforms to one // that sees history //as theattempt to recreate and explain the significant events of the past。
主句：modern practicemost closely conforms to one;从句：让步状语从句While there arealmost as many definitions of history as there are historians;比较状语从句as there are historians;定语从句thatsees history as the attempt to recreate and explain the significant events ofthe past修饰one。主干结构是While there are almost as... asthere are... +主句，While引导让步状语从句，此句与汉语句序复合汉语习惯未作调整，仍放于主句前。从句中as... as结构是比较级，这句话直译为“有多少历史学家，就有多少关于历史的定义。
【参考译文】
几乎每个历史学家对史学都有自己的界定，但现代史学家的实践最趋向于认为，历史学是试图重现过去的重大史实并对其作出解释。
【真题例句2】
In general, the tests work most effectively when thequalities to be measured can be most precisely defined and least effectivelywhen what is to be measured or predicted can not be well defined。
【解析】
可拆分为：Ingeneral, //the tests work most effectively //when the qualities to be measuredcan be most precisely defined //and least effectively //when what is to bemeasured or predicted can not be well defined。
主句：the tests workmost effectively when... and least effectively when...，主句中潜逃了两个并列的时间状语从句whenthe qualities to be measured can be most precisely defined和when...can not be well defined，第二个时间状语从句中又嵌套了一个主语从句what is to bemeasured or predicted做此状语从句的主语。本句在翻译的时候将一个主从复合句，适当调整成了两个独立的单句(即：the tests work most effectively when...,and the tests work least effectively when.。。)，并把两个状语分别提前了，更符合汉语表达习惯。
【参考译文】
一般地说，当所要测定的特征能很精确界定时，测试最为有效;而当所要测定或预测的东西不能明确地界定时，测试的效果则最差。