23考研英语备考 | 必备基础语法(18)-目的、条件状语从句

一、构成

Structure

  从句部分是用以补充说明主句中谓语动词发生的目的的状语从句是目的状语从句。目的状语从句可以由that, so that, in order that, lest, for fear that, in case等词引导。

    在句子中做条件状语的从句称为条件状语从句。可置于句首、句尾，有时还可置于主语和谓语之间。连接词为if、unless、as/so long as等，通常译为“假如”、“如果”。

二、基本用法

Application

1.目的状语从句：

The boss asked the secretary to hurry up with the letters so that he could sign them.

老板要秘书赶快把信写好，以便他签字。

Better takes more clothes in case the weather is cold.

最好多带些衣服以防天气变冷。

He works hard in order that his family may be happy.

为了让家人幸福，他努力工作。

I am telling you that lest you should make a mistake.

我告诉你这一点，以免你搞错。

2.  条件状语从句：

If you ask him,he will help you.

如果你请他帮忙，他会帮你的。

You will certainly succeed so long as you keep on trying.

只要你继续努力，你一定会成功的。

You will fail to arrive there in time unless you start earlier.

如果你不早点动身，你就不能及时赶到那儿。

I can tell you the truth on condition that you promise to keep a secret.

我可以告诉你真相，条件是你答应保密。