what is what, which is which与who is who

三、who is who

who is who的意思是“谁是谁”“人们的情况(姓名、工作、身份等)”，通常与动词know, learn, remember等连用。如：

It was so dark I couldn’t tell who was who. 光线很暗，我分不清哪个是哪个。

I don’t know anyone at this party; you must tell me who’s who. 这晚会上我一个人也不认识，你要告诉我哪个是哪个(即给我作介绍)。

You’ll soon find out who’s who in this department. 你很快就能弄清楚这个部门每个人的情况。

When I go to those family reunions, I can never remember who’s who. 我去参加那些家庭团圆聚会时，从来记不住谁是谁。

注：大写的Who’s Who意为“名人录”“名人词典”。如：

Who’s Who states he retired in 1980. 《名人录》上说他于1980年退休了。

The guest list reads like a Who’s Who of top American businessmen. 宾客名单读起来像是美国顶级商人的名人录。