(2) 关于 since 与 as： 两者所表示的原因都是人们已知的，即对已知事实提供理由，而不是表示直接原因。since 比 as 语气稍强，且比 as 略为正式，它们引导的从句通常放在主句之前，有时也放在主句后：

　　As you weren't there, I left a message. 由于你不在那儿，我留了个口信。

　　Since you are wrong, you should apologize. 你既然错了，就应该道歉。

(3) 关于 for：是并列连词(其余三者为从属连词)，有时不表示因果关系，而是对前面分句内容的解释或推断, 放在主句之后。

　It must have rained last night, for the ground is wet this morning.

　昨晚一定下过雨，你看今天早上地面是湿的。

2．结果状语从句

结果状语从句可以由so that(因此)，so...(that)(如此......以至于)，such...that(这样......以至于)等词引导。

Try to translate the following sentences into Chinese:

1. He didn't plan his time well，so that he didn't finish the work on time.

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2. He didn't finish his homework，so (that) he was punished.

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3. He ran so fast that I couldn't catch up with him.

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4. She is such a good teacher that all of us love and respect her.

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5. They are such interesting books that I want to read them once again.

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归纳： so foolish　　　　　 such a fool　　　　　　　

so nice a flower　　　　 such a nice flower　 　　

so many / few flowers　 such nice flowers　　　　so much / little money such rapid progress　　　

so many people　　　　　 such a lot of people　

3．目的状语从句

目的状语从句可以由so that，in order that，in case(以防)等词引起。目的状语