My mother is busy the room.A. cleanB. to cleanC. cleaningD. cleans

问题补充：

My mother is busy the room.

A. clean

B. to clean

C. cleaning

D. cleans

答案：

A. clean

B. to clean

(答案→)C. cleaning

D. cleans

解析：根据题干可知，此句考查的重点是固定短语be busy doing sth表示忙于做某事，本句的含义是妈妈正忙着打扫房间，故选C。