關系代詞which用法說明

1. 既可引導限制性定語從句，也可用作非限制性定語從句。如：

This is the photo (that) I took. 這就是我拍的照片。

The river, which flows through London, is called the Thames. 這條流經倫敦的河叫泰晤士河。

2. which引導定語從句時，它在從句中主要用作主語或賓語，但有時也可用作定語，在意義上大致相當于this或that。如：

We told him to consult the doctor, which advice he took. 我們叫他去看醫生，他聽取了我們的勸告。

He is studying economics, which knowledge is very important today. 他學經濟學，這種知識現今很重要。

注意，它與用作定語的關系代詞whose用法不同——whose引導定語從句時，它在意義上大致相當于one’s。如：

Wolves are highly social animals whose success depends upon cooperation. 狼是高度群體化的動物，它們的成功依賴于合作。

3. 關系代詞which原則上只指物，不指人；指人要用who。但是，有時指的不是具體的某人，而是指人的屬性（如職業、身份、地位、職務、品質、特征等），則要用which 而不用who。如：

He talked like a scholar, which he was not. 他說起話來像個學者，其實他沒什么學問。

She talked like a native, which she hardly was. 她說起話來像是個本地人，其實她不見得是。

They accused him of being a traitor, which he was. 他們指控他是叛徒，他真是叛徒。

4. 注意不要一看到句前有逗號，就以為一定要用which來引導非限制性定語從句。如以下幾句逗號后的that均不能換成which（原因是逗號前的句子為狀語從句）：

If a book is in English, that means slow progress for you. 如果一本書是用英語寫的，那就意味著你要讀慢些。

If he’s only interested in your looks, that just shows how shallow he is. 如果他只對你的相貌感興趣，那就說明他相當淺薄。

When I say two hours, that includes time for eating. 我說兩小時，那是包括了吃飯的時間。

5. 比較下面兩句，第一句用了連詞but，其后用them；第二句沒用連詞but，其后用which：

She wrote a lot of novels, but none of them were popular.=She wrote a lot of novels, none of which were popular. 她寫過許多本小說，但沒有一本是受歡迎的。

6. 有時可以見到“介詞+關系代詞+不定式”這樣的結構（可視為一種緊縮的定語從句）。比較：

She must have time in which to grow calm.=She must have time in which she can grow calm. 她必須有冷靜下來時的時間。

She had some money in the bank, with which to help her mother.=She had some money in the bank, with which she could help her mother. 她銀行里有些錢用來幫助她的母親。

值得指出的是，這類結構中的介詞不能沒有，并且該介詞也不能位于不定式后面，比較：

There the children had a garden in which to play.（很正式）

There the children had a garden in which they could play.（較正式）

There the children had a garden to play in.（較口語化）在那兒孩子們有個可以玩耍的花園。

但是不能說：There the children had a garden which to play in.

7. 有時可見到由which引導的非限制性定語從句單獨成句。如：

Mary is enormously respected. Which is not to say you are not an exceptionally able lady. 瑪麗非常受尊重，但這并是說你不是一位極為能干的女士。