问题补充：
Without electricity human life quite different today.
A. is
B. will be
C. would have been
D. would be
答案：
A. is
B. will be
C. would have been
(答案→)D. would be
解析： 考查虚拟语气。Without electricity是一种含蓄虚拟条件，相当于if引导的条件状语从句，指现在的情况，所以主句human life quite different today要用would+do的虚拟语气。选D。
