If you have lost a library book you have to it. 　　A. find outB. look afterC. pay forD. ta

问题补充：

If you have lost a library book, you have to it.

A. find out

B. look after

C. pay for

D. take care

答案：

A. find out

B. look after

(答案→)C. pay for

D. take care

解析：句意：如果你弄丢了图书馆的书，你不得不赔。A找到，查出B照顾C为……付款D小心。根据句意，故选C。