If I had V-ed, I would ……
结构︰If…had 过去分词…，主词 would/should 等 原形动词 now/today
说明︰这是<时态>不一致时的假设<句型>，亦称混合假设条件句。即：if <子句>若与过去事实相反，用<过去完成式>表示;而<主要子句>若与现在事实相反，则用过去式<助动词>表示。此类<主要子句>句尾通常有表现在的<时间副词>，如 now，today 等。
If he had worked harder when young, he would be well off now.
如果他年轻时多努力一点，现在就能过得舒服些。
If I had been rich ten years ago, I could buy that house today.
如果十年前我有钱，今天我就能买下那栋房子了。
Had he told the truth, he wouldn't be punished now.
如果他当时肯说实话，现在就不会受罪了。
Had he followed the doctor's advice, he might be alive now.
当时他要是听了医生的建议，现在可能还活着。
