He was wandering in the park, ________ his time watching the children playing.

A.saving

B.killing

C.sparing

D.costing

答案及解析： B

解析：

从was wandering…可知，他在“消磨、打发时间”。kill one's time常译为“消磨、打发（时间）”。A，C，D三项都不具有此意。