In retrospect, I missed a great opportunity to make a fortune.

回想起来，我错过了一个发财的好机会。

The police found a clue from the retrospect of the incident.

警方从对事件的回顾中发现了一条线索。

This retrospect is just to commemorate our lost youth.

这次的回顾只是为了纪念我们逝去的青春。

The decision seems extremely odd, in retrospect.

回想起来，这个决定显得极其荒谬。

In retrospect, I wish that I had thought about alternative courses of action.

回想起来，我真希望自己当初考虑过其他的行动方案。

In retrospect, I think that I was wrong.

回首往事，我觉得当时我错了。

In retrospect, I was dead wrong.

回想起来，我是大错特错了。

In retrospect it's not surprising.

回想之中也不觉得惊讶了。