因为不可以追问，针对上个问题“虚拟语气中若主句包含宾语从句怎么样安排谓语时态”中老师的回答继续请教。上个问题中老师说主语中的虚拟语气 would have done 不可以用在主语的宾语从句中，但有这么一题（“英语语法网”的语法训练《英语虚拟语气考试知识点训练13题》）：
Thank you very much indeed. If it had not been for your advice I really _____ what I should have done.
A.do not know B.have not known C.had not known D. would not have known.
我选D答案给的A.
请问老师该题如何理解。
在虚拟条件句中，假如主句的宾语是个宾语从句，到底是主句用虚拟语气还是从句用虚拟语气，一般没固定的格式，这需要依据句子的具体语境来确定：
1. 假如主句内容与事实相反，宾语从句内容与事实相符，则主句谓语用虚拟语气，宾语从句谓语用陈述语气。如：
If you went into town, youd notice all the pubs have loud jukeboxes. 你若进城去，你会注意到所有些夜店都有声音非常大的自动点唱机。（all the pubs have loud jukeboxes为客观事实，与事实相符，故用陈述语气）
2. 假如宾语从句内容与事实相反，主句内容与事实相符，则宾语从句谓语用虚拟语气，主句谓语用陈述语气。如：
If we had been spotted at that point, I don’t know what would have happened to us. 假如当时大家被发现了，我不了解会有哪些后果。（I don’t know 指目前的的状况，故用陈述语气，指“目前不了解”）
I hate to think what would have happened if we hadn’t arrived. 我不敢想象当时大家没到达会出现那种情况。（I hate to think指目前的状况，故用陈述语气，指“目前不敢想象”）
▲请看一道高考考试题：
If Newton lived today, he would be surprised by what ______ in science and technology.
A. had discovered B. had been discovered
C. has discovered D. has been discovered
本题答案为D。此题可用排除法来做。依据what与discover的关系可知，此处应用被动语态，即指被发现的东西，故可排除选项A和C；因为句首用了非真实的条件句（即虚拟条件句）， 所以此题的迷惑性非常大，很多考生会误选B。其实，因为句中的虚拟语气是对现的状况进行假设（注意句中的today），所以主句谓语用了 would be 与其呼应，而“在科学和技术方面所获得的发现”指的是目前的事实，而非假设，所以此处要用目前完成时，而不可以用过去完成时。即答案选D，而不是B。
▲语法网上这道题的剖析：
Thank you very much indeed. If it had not been for your advice I really _____ what I should have done.
A.do not know B.have not known C.had not known D. would not have known.
本题之所以选 A，是由于 I don’t know 指目前的状况，即：假如当时不是听了你的建议，我目前真不了解我当时做发生了什么事来。
■与刘老师探讨，并向刘老师学习！
下面给出以上各句的出处：
If you went into town, you’d notice all the pubs have loud jukeboxes. 假如你进了城，你会注意到所有些夜店都有音量非常大的自动点唱机。（摘自《柯林斯高级英语词典》）
If we had been spotted at that point, I don’t know what would have happened to us. 假如当时大家被发现了，我不了解会有哪些后果。（摘自《柯林斯高级英语词典》）
I hate to think what would have happened if we hadn’t arrived. 我不敢想象当时大家没到达会出现那种情况。（摘自《牛津英语搭配词典》）
另外补充一句：
If it hadn’t been for your help, I don’t know what I’d have done. 要不是你的帮忙，真不了解我当时会如何解决。（摘自《英语使用方法指南》）
其实刘老师的剖析也是有道理的，只不过上面提到的几个句子有的特殊而已。假如网友能综合地理解，对英语学习必然会大有帮助！
