attributive clause/appositive clause(定语从句/同位语从句)

虽然《高级英语语法》(高教出版社,1994,p.794)等英语著作都把上句中的why从句看作是同位语从句,但是我们却认为它是限制性定语从句。应当注意,在the reason why (that)结构中,why或that是关系副词,而不是像在同位语从句中那样是连词。让我们看一看R.Quirk等人对这一结构的分析:

“Where and when, and to a lesser extent why, are also used as relatives…” (CGEL, § 7.53) (“where 和 when 以及较少使用的 why 还可用作关系副词……”)

"The preposition + pronoun can be replaced by special adverbs, eg:

That's the reason $\left\{ \begin{array}{l} ? \text{ for which} \\ \text{ why } \end{array} \right\}$ she spoke. (CGEL, § 17, 18)

(“介词 + 代词”可以用特殊的副词代替,例如……”)

"The rare use of for which after reason strikes most people as clumsy and unnatural, while the reason why seems tautologous; there is general preference for zero [5a] ...

Is that the reason they came? [5a]"(CGEL, § 17.19)

[“reason 之后接 for which 鲜为人用, 因为大多数人都觉得它累赘, 不自然, 而 the reason why 又显得语义重复, 人们普遍喜欢使用零关系副词(例 [5a]……)”]

请注意 CGEL 的作者们把 why 或 that 明确地叫做关系副词, 而把省略掉的 why 或 that 叫做零关系副词。

让我们再来对比一下真正的同位语从句,便可看出 the reason why 与它们之间的区别:

1. The news that we are having a holiday tomorrow is not true. (PEG) 明天放假的消息是不真实的。

2. Your original question, why he did not report it to the police earlier, has not yet been answered. (CGEL, § 15.5) 你最初提出的他为什么不早些报警的问题尚未得到回答。很容易看出，同位语从句的第一个特点，是同位语从句所表达的概念在内涵上应当等同

于其中心词：

the news = we are having a holiday tomorrow

your original question = why he did not report it to the police earlier

而 the reason 与 why 从句却不存在这种关系：

the reason ≠ she refused to go abroad

the reason ≠ she spoke

同位语从句的第二个特点,是可以用中心词作主语,而把同位语从句改为表语从句。此时,句子在内容上是成立的。

The news that we are having a holiday tomorrow is not true. →The news is that we are having a holiday tomorrow.

Your original question, why he did not report it to the police earlier, has not yet been answered. $\rightarrow$ Your original question is why he did not report it to the police earlier.

而 the reason why 却不能这样进行改写：

Could you tell me the reason why she refused to go abroad?

× The reason is why she refused to go abroad.

That's the reason why she spoke.

× The reason is why she spoke.

综上所述可见,在 the reason why(that) 结构中 why(that) 引导的是定语从句,而并不是同位语从句。