引导定语从句。用于such as结构，其中as为关系代词；such as相当于those who；such as 用作关系代词，用法上相当于that或which.

相关介绍：

such as 的用法：

表示举例，such as 意为“例如，诸如此类的，像……那样的”，相当于like或for example。如：

There are few poets such as Keats and Shelly. 像济慈和雪莱这样的诗人现在很少了。

Adverbs are used to modify verbs, such as “quickly” in “she ran fast”. 副词用来修饰动词，例如“她跑得快”中的'“快”。

Animals such as rabbits and deer continue to be active all winter，finding food wherever they can . 像兔和鹿这样的动物整个冬天都是很活跃的，它们到处寻找食物。

用于此义时的几点说明：

(1) 这类结构既可表现为“名词+such as+例子”，也可表现为“such+名词+as+例子”。如：

I enjoy songs such as this one.= I enjoy such songs as this one. 我喜欢像这首歌一样的歌。

(2) 若 such as 后接动词，通常用动名词，有时也可用动词原形。如：

Don't do anything silly such as marry him. 不要做什么蠢事，比如说去嫁给他。

Magicians often perform tricks such as pulling a rabbit out of a hat. 魔术师常常变从帽子里抓出兔子的戏法。

(3) 不要按汉语意思将such as 用作such like。

(4) such as 后不可列出前面所提过的所有东西。如：

正：I know four languages, such as Japanese and English. 我懂四种语言，如日语、英语。

误：I know four languages, such as Chinese, French, Japanese and English. 我懂四种语言，如汉语、法语、日语和英语。