" If I had" and then the conditional tense.

“如果我有”然后是条件时态。

So a slightly alternative use of the conditional tense, here.

因此，这里稍微替代了条件时态的使用。

You could have your conditional tense followed by " if" , followed by past simple.

你可以让你的条件时态后跟“如果”，然后是过去的简单。

This is the conditional tense of regret, wishing that the past was different.

这是遗憾的条件时态，希望过去有所不同。

So, we have four sentences, there are four conditional tenses, so one of those goes in each.

所以，我们有四个句子，有四个条件时态，所以每个都有一个。

Okay, so I hope that's been a useful overview of the four conditional tenses and clarified how to construct them.

好的，我希望这是对四种条件时态的有用概述， 并阐明了如何构造它们。