英语高手请进关于虚拟语气的问题

题目

英语高手请进关于虚拟语气的问题
有一种：从句对过去虚拟,主句对现在或将来虚拟的混合情况主句用
would/could+do
还有一种：从句对过去虚拟 主句用would/could/+have do
这两种到底有何区别?有如下例子如何解?
1.if your missing son _safe and sound yesterday you_now
A hadn't teturned ;couldn't be so relieved
B hadn't teturned ;couldn't have been so relieved
2.if only he_the medicine as the doctor instructed ,he would not suffer somuch now
A took B had taken

答案

1A2B你的这两道题目,都是你说的第一种.就是if条件句是与过去事实相反的, 主语是与现在事实相反的.这从时间状语就能看出来.第一题,if从句的状语是yesterday,与过去事实相反,就用过完.主句状语是now, 与现在事实相反,...