30．When you finish your work don’t forget to put the tools back where they ．A. areB. will

问题补充：

30．When you finish your work, don’t forget to put the tools back where they ．

A. are

B. will be

C. were

D. had been

答案：

A. are

B. will be

(答案→)C. were

D. had been

解析：考查动词时态。把工具放在原处。既然是原来所在的地方，很显然时态应为过去式。