Question

When he knocked at the door, my mother was busy ____ supper.

A. preparing for                                   B. in preparing

C. to prepare for                                 D. to prepare

Answer 1

B

解析:

“be busy (in)doing something” 忙于干谋士，要求接动词的-ing形式。准备的直接宾语是“supper”,故其前面不用介词for。