Sally is busy her homework.A. inB. atC. withD. on

问题补充：

Sally is busy her homework.

A. in

B. at

C. with

D. on

答案：

A. in

B. at

(答案→)C. with

D. on

解析：考查固定结构。Be busy with sth.忙于某事；be busy doing sth.忙于做某事。所以选 C。