(fact: You often go to bed late, so you are always sleepy in the morning.)
　　If this were the case, it would be very awkward.
　　(fact: This is not the case, so it is not awkward.)
　　Now let’s do some translation:
　　要是没有虚拟语气，英语就会容易多了。
　　If there were no subjunctive mood, English would be much easier.
　　如果我是你，我就在房屋周围种些树。
　　If I were you, I would (should) plant some trees around the house.
　　如果我把头发染成蓝色，人人都会笑话我。
　　If I dyed my hair blue, everybody would laugh at me. Or: I would (should) be laughed at by everybody.
　　要不是她这么忙，她就会出席今天下午的会议了。
　　If she were not so busy, she would attend the meeting this afternoon.
　　2、对过去的虚拟，表示与过去的事实相反的假设时，条件状语从句的谓语动词用过去完成时,主句的谓语动词用would (should, could, might)+过去分词。见下表： 条件状语从司的动词形式
主句的动词形式

If+主语+had+过去分词
i(we)should+have+过去分词
主语+could (might,could)+have ＋ 过去分词

　　例句：
　　If you had taken my advice, you wouldn’t have failed in the examination.
　　(fact: You did not take my advice, so you have failed in the examination.)
　　I would have checked my paper again if I had had more time at yesterday’s examination.
　　(fact: I did not have more time at yesterday’s exam, so I didn’t check my paper again.)
　　He would have already recovered from his illness if he had seen the doctor in time. (fact: He didn’t see the doctor in time, so he has not recovered from his illness.)
　　If we had known that she was to arrive yesterday, we could have met her at the station.
　　(fact: We didn’t know that she was to arrive yesterday, so we could not meet her at the station.)
　　You didn’t let me drive. If we had driven in turn, you wouldn’t have got so tired.
　　(fact: We didn’t drive in turn, so you have got so tired.)
　　Now let’s do some translation:
　　要是有人警告过他，他就不会吃那个食物了。
　　If he had been warned, he would not have taken that food.
　　如果你服从命令的话，灾难就不会发生了。
　　If you had obeyed the order, the disaster could not have happened.
　　假如你早接受了那个有经验的老工人的意见，你的试验就不会失败了。
　　If you had taken the old experienced worker’s advice, you wouldn’t have failed in the experiment.
　　如果我知道你要来的话，我就去机场接你了。
　　If I had known that you were to arrive, I would have met you at the airport.
　　如果我的律师上周六在这里，他就会阻止我去了。