If you don’t know the words, you must _____

试题详情及答案解析

If you don’t know the words, you must ______in a dictionary.

A．look it up	B．look up it
C．look them up	D．look up them

答案：C

试题分析：句意：如果你不知道这些单词，你必须在字典中查找。look up,动词加副词构成的动词短语，加代词做宾语，要放中间。根据句意，可知指代上句中的名词复数words,故用代词them.故选C。
考点：考查动词短语的用法。