He does so little work in the office that for all practical purposes it would make no diff

问题补充：

He does so little work in the office that for all practical purposes it would make no difference he didn’t come.

A. if

B. when

C. why

D. whether

答案：

(答案→)A. if

B. when

C. why

D. whether

解析：本题易误选D。根据句意“他在工作中是一个不足以轻重的人，所以如果他不来也不会有什么影响”，可以看出if符合逻辑。