答案：D

题目分析：句意：要是没有电，人类的生活会和今天有很大的差异。本题重在理解without虚拟语气的用法：

1. 与现在事实相反：Without air, man couldn't exist on the earth.没有空气的话，人类将不能在地球上生存。

谓语动词：would/could/might (not) do sth.

2. 与过去事实相反：Without your help, I would have failed the exam last week.没有你帮助的话，我上周考试可能就通不过了。

谓语动词：would/could/might (not) have done sth.

3. 与将来事实相反：Without your ticket, I wouldn't be able to go to the concert tomorrow.要是没有你的票的话，我明天就不能去听音乐会了。

谓语动词：would/could/might (not) do sth.

点评：虚拟语气是高考每年的必考点，用法较多，平时学习应积累巩固。