虚拟语气从句中过去将来时的这四个助动词都可以用吗?

除了if条件从句,能够用虚拟语气的从句还有以下几种,但是并不是所有的从句都可以用 would,should,could,might：
一、名词从句
当名词从句表示主语的个人的意愿时,从句中要用 should do 或省略 should 直接用动词原形,如：
They suggested that he (should) do it before Sunday.(宾语从句)
Their order is that he (should) have to stop at once.(表语从句)
It is important that he (should) read more in his spare time (主语从句)
二、目的状语从句 so that 和 in order that 只用 can/could,may/might,如：
I stopped so that you could catch up.我停下来以便你能赶上.
Mail your package early so that you could ensure its timely arrival.早点寄出你的包裹以便保证它能及时寄到
In order that we might get there on time,we have to start early.为了可以及时赶到那里,我们必须早点儿出发.
三、几个特殊的 that 从句,would,should,could,might 可根据不同的情态分别使用,如：
It's high time that you started working.你早该开始工作了.I'd rather that you would come earlier tomorrow.我宁愿你明天早些来.
He'd better that he could help you.要是他能够帮你就好了.
I wish that you might give me an early reply.我倒希望你会尽早答复我.
四、补充问题回答
总述：这四个情态动词除了在 if only 句子中 should 有时用于表示对将来的虚拟外,都可以表示对现在的虚拟.
1.wish+主语+would/should/could/might+动词原形：意思是“但愿XX(愿意/应该/能够/可能)就好了”,
2.if only+主语+ would/should/could/might+动词原形：其实就是由条件从句省略主句脱胎而来,意思是“要是XX(愿意/应该/能够/可能)...多好”
但是有时候 if only one should do 表示要是将来有可能就好了,需要分析上下文,去判断究竟是表示“现在应该”还是“将来有可能”.
3.would rather+主语+ would/should/could/might+动词原形：表示“宁愿现在XX(愿意/应该/能够/可能)做某事”
4.as if+主语+ would/should/could/might +动词原形：完全可以用条件从句的虚拟要求使用,只不过意思成了“好像、似乎、仿佛”.
补充：
对不起,原答案吧其实就是由条件从句省略主句脱胎而来写成了“主语”,让你误解了.