Hello大家好，今天我们来讲解一下在托福阅读中状语从句的作用吧！同学们对状语从句的了解有多少呢？让我们先来看一下状语从句的定义：
状语从句是用一个句子修饰主句的谓语动词或整个主句，用来表示时间，地点，原因，目的，结果，条件，方式，比较，让步等。
那我们如何识别状语从句呢？同学们来看下有哪些关键词来帮我们识别吧！
时间状语从句有以下常见关键词：
when, as, while, whenever, after, before, till (until), since, once, as soon as, the second, no sooner…than;
原因状语从句有以下常见关键词：
because, since, as, now that
地点状语从句有以下常见关键词：
where, wherever, anywhere, everywhere
目的状语从句有以下常见关键词：
so, so that, in order that, in case;
结果状语从句有以下常见关键词：
so that, so…that, such…that
条件状语从句有以下常见关键词：
if, unless, so long as, as long as, on condition that, as far as, if only , if
让步状语从句有以下常见关键词：
although, though, even if, however, whatever
方式状语从句有以下常见关键词：
as, as if, the way, rather than
比较状语从句有以下常见关键词：
than, so…as, as…as, the more…the more
同学们可以熟悉一下以上提到的关键词，因为当我们在长难句中碰到状语从句时，我们可以凭借以上的关键词断开从句，把一个句子当成两个句子去理解。
了解了这些知识点之后，我们用一个例句来试一下吧：
例句1:
William Smith taught himself surveying from books he bought with his small savings when he grew older and at the age of eighteen he was apprenticed to a surveyor of the local parish.
这个句子有点长，结合我们之前说过的知识点，同学们觉得在哪里断句比较合适呢？我们可以在“when"这里把句子断开，现在来看看断开之后这个句子是否更加好理解了。断开之后这个句子可以被分为两个部分。when后面的句子为时间状语从句，描述William长大之后的事情：
#1: William Smith taught himself surveying from books he bought with his small savings.
#2: when he grew older and at the age of eighteen he was apprenticed to a surveyor of the local parish.
断开句子之后是不是更加好理解了呢？我们再来试一个吧！
例句2:
The increasing use of dried animals waste as a substitute fuel has also hurt the soil because this valuable soil conditioner and source of plant nutrients is no longer being returned to the land.
同学们回顾一下我们刚才讲的知识点，这个句子在哪里断开比较合适呢？
我们可以在because这里来断开因为从because这里就是在解释原因了，为原因状语从句，解释为什么dried animal waste也会伤害土壤：
#1: The increasing use of dried animal waste as a substitute fuel has also hurt the soil
#2: Because this valuable soil conditioner and source of plant nutrients is no longer being returned to the land.
对状语从句的讲解就到这里啦。总结一下：同学们之后看到句子里有以上关键词的时候，可以尝试断句来辅助自己更加清晰的去理解句子～更多有关状语从句的练习可以移步我们的赠送资料哦！我们下次再见啦！
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