一个关于虚拟语气的英文the student asked her professor if he would have

一个关于虚拟语气的英文
the student asked her professor if he would have gone on the space ship had he know earlier
if从句 主句
对现在虚拟 过去式 would do
对过去虚拟 过去完成时 would have done
对将来虚拟 过去式/should do/were to do would do
按照这样的话,if 后面为什么是 would have gone 还有为什么要倒装had he know