I forgot his telephone number I want to in the telephone book.A. look after itB. look up

问题补充：

I forgot his telephone number, I want to in the telephone book.

A. look after it

B. look up it

C. look it up

D. look for it

答案：

A. look after it

B. look up it

(答案→)C. look it up

D. look for it

解析：句意：我忘了他的电话号码，我想在电话本上查看。Look after照顾；look for寻找；look up查阅，当宾语是代词是时候放在动词和副词中间，故选C。