The kids are kept( ) tidying up the desk. A. busy with B. busying with C. busy in D. to busy in

答案为C。本题考查固定搭配。A项 be busy with 表示“忙于做某事”，但后接名词，不接动名词，所以被排除；B项中busying的表达是错误的；D项中多了介词to，也不对。只有C 才符合be (kept) busy (in) doing sth. 结构。