I have to amuse myself by looking after my 10－month baby since I have nothing important to

问题补充：

I have to amuse myself by looking after my 10－month baby since I have nothing important to workthese days.

A. in

B. during

C. on

D. for

答案：

A. in

B. during

(答案→)C. on

D. for

解析：work on“从事……工作”，宾语是nothing。these days“这些天来”，是时间状语。