Question

if you had asked him beforehand

If you had asked him yesterday,you __________ (know) what to do now.填什么 为什么.
别所答非所问.这是虚拟语气

Answer 1

虚拟语气情境下与现在事实相反的用法是
从句:动词的过去式（be的过去式一般用were）
主句:would/ should/ could/ might + 动词原形
所以答案应为：you (should know)
或者 you (would know)
另外提供另外两种虚拟语气不同情境的用法：
与过去事实相反 :
从句 :had + 过去分词
主句 :would/ should/ could/ might + have + 过去分词
与将来事实相反 :
从句:动词过去式,should + 动词原形,
主句 :were to + 动词原形 would/ should/ could/