非限定關係子句

非限定關係子句會就句中論及的人事物額外補充資訊，但這些資訊並不會指明它談的是何者。就拿這個例句來說：Gorillas, which are large and originate in Africa, can sometimes be found in zoos. 在這個句子中，我們談的是「所有大猩猩」，而不是只有其中幾隻。非限定關係子句會多加補充有關一般大猩猩的資訊，不會限定群體或單一隻大猩猩。如果非限定關係子句從句中移除，剩下的句子文法上仍是正確的，整句話的意思不會有太大的改變，頂多少了些資訊罷了。

非限定關係子句必定包含關係代名詞和動詞，有時也會包含動詞的主詞或受詞，可有可無。非限定子句一般會用逗號或括號來與主要子句隔開。

測驗您的知識

舉例

John's mother, who lives in Scotland, has 6 grandchildren.
My friend John, who went to the same school as me, has just written a best-selling novel.
My grandmother, who is dead now, came from the North of England.
We stopped at the museum, which we had never visited before.
I've just come back from London, where John lives..
Yesterday I met a woman named Susan, whose husband works in London.

關係代名詞

以下的關係代名詞是用在非限定關係子句，置於非限定子句的句首，而關係代名詞指的是前面提到的名詞。

	人	事物	地方
主格	who	which
受格	who/whom	which	where
所有格	whose

非限定關係子句與限定關係子句的差別

在英語口頭上，限定關係子句常用 that 來取代 who、whom 和 which 等代名詞。但在非限定關係子句中，就不能用 that 來取代其他關係代名詞，也不能像限定關係子句一樣省略關係代名詞。在非限定關係子句中，關係代名詞是不可或缺的，就算關係代名詞是子句中的受格，也不能省略。非限定關係子句一般會用逗號來與主要子句隔開，而限定關係子句通常不用逗號分隔。

舉例

He gave me the letter, which was in a blue envelope.（非限定子句：信只有一封，而且是藍色的；這時您必須用 which。）
He gave me the letter which/that was in a blue envelope.（限定子句：信不只一封，而且顏色有很多種，而他給我的是藍色的那封信。which 可以被 that 取代，並且不用加逗號。）
He gave me the letter, which I read immediately.（非限定子句：信只有一封，而 which 是動詞 read 的受詞，但不能省略。）
Stratford-on-Avon, which many people have written about, is Shakespeare's birthplace.（介系詞一般會放在關係子句的句尾。）
Stratford-on-Avon, about which many people have written, is Shakespeare's birthplace.（書面用語上常會將介系詞放在代名詞前。）

在非限定子句的引導詞

在關係代名詞前，可以用 all of 或 many of 來引導非限定子句。

	人	物
all of, any of, some of, a few of, both of, each of, either of, half of, many of, most of, much of, none of, one of, two of 等	whom	which

舉例

There were a lot of people at the party, many of whom I had known for years.
There are 14 girls in my class, a few of whom are my friends.
He was carrying his belongings, many of which were broken.
He had thousands of books, most of which he had read.
He picked up a handful of stones, one of which was sharp.