in retrospect
When you consider something in retrospect, you think about it afterwards, and often have a different opinion about it from the one that you had at the time.
with hindsight
with foresight
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, it was a role he should have avoided, but fatigue and a lack of direction played their part in the choice.
回想起来,这是一个他应该避免的角色,但他当时做选择时他既疲惫又迷茫。