if i had done与if i would have done的区别好像两者都是对过去的虚拟

Question

if i had done与if i would have done的区别好像两者都是对过去的虚拟，但是后者我以前并没有见过，刚刚看到，有哪位帮我，谢了

Answer 1

if i had done 是说 假设这个事情 我确实做了
if i would have done 是说 假设这个事情在以前会发生，其实根本不可能发生， 这个用的少
举个 if i would have had time, i would have been with u ，假设有时间，但是我根本不会有
这个和 if i had had time 的区别是 had had 就是假设一定有时间了，
虽然看上去效果一样，但是前者更能体现出无奈的那种感觉。
用 could have 举例，应该明朗一些。
if i could have 表示 这个事情我在以前可以做，但是并不能够。
举个例子，你朋友以前请你帮忙，但是你帮不了，事后，你对他说 i apologize, if i could have，i would have helped u. 实在抱歉，如果我可以的话（其实不可以）我绝对会帮你。

Answer 2

前者是对过去的虚拟，但英语里不可能有if I would have done 这样的表述！本回答被网友采纳

Answer 3

　　条件状语从句对过去的虚拟结构是从句用过去完成时had done, 主语用would have done的形式，并没有从句If用 would have done的形式。
例1：If Mary had studied hard, she would have passed the final exam.
如果Mary 努力学习的话，她期末考试就会及格了。（表示她考试不及格，对过去的虚拟）。
例2：If I had known her phone number, I would have called her in time.
如果我有她的电话号码，我就会及时打电话给他。
　　条件虚拟语气还有一种省略if的形式，如果省略了引导词if，则从句需要倒装。
例3：HadMary studied hard, she would have passed the final exam.
如果Mary 努力学习的话，她期末考试就会及格了。
例4: HadI known her phone number, I would have called her in time.

　拓展：
　　条件虚拟对现在虚拟的结构是从句用一般过去式，主句用would do形式。
例1：If I were you, I would try it again.
如果我是你的话，我会再次尝试。
例2（倒装形式）：Were I you, I would try it again.
如果我是你的话，我会再次尝试。
　例3：If we had a washing machine, my mother would be happy.
　如果我们有洗衣机的话，我妈妈会很开心。

Answer 4

……你说的是哪道题？