定语从句之九：关系副词：why

    在复合句中，修饰名词或代词的从句叫定语从句，被修饰的名词或代词叫先行词，引导定语从句的连词叫关系代词（who, whom, whose, that, which, as）或关系副词（when, where, why, how），它们在从句中必须作成分，现归纳总结如下：

关系副词 why 的用法：

要点：引导限制性定语从句，修饰先行词是表示原因的名词，连词在从句中作原因状语，

具体如下：

1．引导限制性定语从句，修饰先行词是reason, explanation, excuse等表示原因的名词，

   连词在从句中作原因状语，有时可换成for.+ which，如：

1).Do you know the reason why she was late?

   = Do you know the reason for which she was late?

   你知道他迟到的原因吗？

2).The reason why Peter failed was his laziness.

   = The reason for which Peter failed was his laziness.

   彼得失败的原因是他的懒惰。

3).This is the reason why the computer cannot entirely replace man.

   = This is the reason for which the computer cannot entirely replace man.

   这就是计算机不能完全代替人的原因。

4).I don’t know the reason why she was absent.

   = I don't know the reason for which she was absent.

   我不知道她缺席的原因。

5).The reason why the scientist failed is not clear.

   = The reason for which the scientist failed is not clear.

   这位科学家失败的原因还不清楚。

6).The reason why the patient doesn't eat it is that he hates it.

   = The reason for which the patient doesn't eat it is that he hates it.

   病人不吃它的原因是他厌恶它。

7).We cannot accept the excuse for which you were absent.

   = We cannot accept the excuse for which you were absent.

   我们无法接受你缺席的借口。

8).This is the explanation why he changed his plan.

   = This is the explanation for which he changed his plan.

   这是他改变计划的解释。

9).I think I can understand the reason why he didn't tell the truth to me.

   = I think I can understand the reason for which he didn't tell the truth to me.

   我认为我能理解他为什么不对我讲实话的原因。

2．先行词虽是原因名词，但连词在从句中作主语或宾语时，还要用that或which，作宾语时，连词可以省

   略，(但连词作prep.的宾语且介词提前时不能省略)，如：

1).The reason (that/which) he told me sounded reasonable.

   他告诉我的原因听起来有理。

2).No one believes the reason that he gave us about his absence at the meeting.

   没有人会相信他给我们缺席会议的原因。

3．that 也可以用于表示原因的名词后，替代 why，在从句中作原因状语，如：

1).The reason (that) he missed the train was that he got up late.

   他误了这班火车的原因是他起床迟了。

2).This is the reason (that) he came late.

   这就是他迟到的原因。

3).Do you know the reason (that) he didn't attend the meeting yesterday morning?

   你知道他昨天上午不参加会议的原因吗？

4).This is the very reason (why) I told you to keep it secret.

   这是我告诉你要保密的唯一理由。