if he had worked hard at high school ,he would be a college student like you today
问题描述：
if he had worked hard at high school ,he would be a college student like you today
为什么是would be不是had been
答
这是个混合型的虚拟语气句子,从句if是在讲过去：要是他当时在高中时有好好学的话；主句讲的是现在（today）,那么今天他就会像你一样也是个大学生了.要用would do.
...would have done是对过去发生的事的虚拟,“本会.”.