examination had you gone and explained that your parents were ill at the time.

　　该句前半句用的是假设虚拟，后半句主句也用的是假设虚拟（如果你去并且解释的话），但是后半句的从句用的是事实语气，因为"父母病了"是客观事实，故不需要用虚拟形式had been。

6. 含蓄虚拟条件句

　　含蓄条件句是指句中没有明显的虚拟条件句，而是利用其他手段来暗示存在虚拟条件。但是这类隐含式虚拟条件句往往都可以转化为if引导的条件句。常来表示含蓄虚拟条件的手段有：

（1）介词或介词短语，如but for, but that, without, in case of, under more favorable condition等。

　　Without the leadership of the party, we could not be living a happy today.=If there hadn't been the leadership of the party, we could not be living a happy today.

A. In spite of B. But for C. Because of D. As for 答案选B。

　　(2)连词，如：so that, unless, in case, supposing, lest, provided(倘若......)，for fear that(唯恐)，in order that, on condition that, if only(要是......就好了)等。

　　She listened carefully in order that she might discover exactly what he wanted. =if she listened carefully, she might discover exactly what he wanted.

　　If only I had more money, I could buy a car.

　　(注：lest, for fear that 和 in case 引起的从句中谓语动词多用should+动词原形，但可以不用虚拟语气，而用动词的陈述语气形式。)例如：

　　The foreign teacher spoke slowly in case we misunderstood him. 这位外籍教师说得很慢以免我们听不懂。

Care must be taken in using this method lest overflow should occur.在使用此法时要小心谨慎，以免会发生溢流现象。

II: wish 后的 that 从句中:

1. 表示现在或将来的愿望,从句中过去式.

I wish I knew his address.

I wish I were young.

2. 表示过去没有实现或不可能实现的愿望, 从句用过去完成式或would, could, might + have + 过去分词.

I wish you had written to him.

I wish I could have slept longer this morning, but I had to get up and come to class.