It is quite an informal party; you needn’t for it.A. look upB. dress upC. put upD. take up

问题补充：

It is quite an informal party; you needn’t for it.

A. look up

B. dress up

C. put up

D. take up

答案：

A. look up

(答案→)B. dress up

C. put up

D. take up

解析：本题的含义是这个聚会相当不正式，你不需要为此而穿着打扮，dress up表示穿着打扮的意思，符合题意，故本题选B。