If I were you, I would go to bed early tonight. 如果我是你，我今晚就会早点睡。
If you took the bus, you would be late for the film. 如果你坐公车去看电影，那么你就会迟到。
If Jack had scored that goal, we would have won the football match. 如果杰克射进了那个球，我们就会赢得那场足球比赛。
If she hadn't come, I might have been in trouble. 如果她没来，我可能已陷入困境了。
I could help you if you had difficulty in doing your homework. 如果你做作业有困难，我会帮助你的。
If it were to rain tomorrow, they would not go out. 如果明天下雨的话，他们就不会出去。
表示与现在事实相反动词的过去式（过去时）Could/ should/ would/ might + 动词原形
表示与过去事实相反Had + 动词的过去分词 （过去完成式）Could/ should/ would/ might + have + 动词的过去分词
should/ were to+ 动词原形Could/ should/ would/ might + 动词原形
1.If he my advice, he wouldn't have lost his job.
A. followed B. should follow C. had followed D. would follow
If I had enough money, I would travel around the world.
If I should see / were to see / saw him tomorrow, I would invite him to my house.
（1）省略if, 用 "were, had, should + 主语"。如：
Were she my daughter, I wouldn't allow her to study abroad. 如果她是我女儿，我就不让她出国学习了。
Had I worked hard, I would have surely succeeded. 如果我当时努力学习的话，我肯定会成功的。
Should there be a meeting tomorrow, I would come. 如果明天有会议，我会来。
（2）含蓄条件句。虚拟语气句中不出现if 条件句，而是用介词、介词短语或连词通过上下文表现出来，这时须根据句子的含义判定是用虚拟现在式还是虚拟过去式。常见短语有：but for, without, otherwise, or 等。如：
Without your help, I wouldn't have succeeded. (= If you hadn't helped me, I wouldn't have succeeded.) 没有你的帮助，我就不会成功。
But for your advice, I would have failed.(=If you hadn't given me advice, I would have failed.) 如果不是你的建议，我会失败的。
1. the president, I allow the poor students to enter the university for free.
A. Were I; will B. Am I; will C. Were I; would D. Am I; would
2.Without your help, we _________ so much.
A. will not