If you don't know a word,you can __in a dictionary.

问题描述:

If you don't know a word,you can __in a dictionary.
A.look it up
B.look for it
C.look at it
D.look after it

look up 查阅查寻 指的是查字典,或者电话号码簿
而it因为是代词,需要放在中间