How we can say: it is easy to understand what you could have done to prevent something bad from happening after it has happened


Imagine someone asks you a question and you don't know the precise answer and when they say you, you say: "oh, I knew it." for example:

Andy: Do you know the what would be sinA in this triangle?

Kevin: Yes, of course. let me think! Aha. Got it. It would be AC divided by BS (AC/BS).

Andy: No Kevin. You're answer was incorrect. It is vice versa. AC/BC.

Kevin. Oh, I knew it.

Andy: Yea (smilingly) [every question will appear to be easy when you know it's answer. (whereas Andy knows the answer already.)]

But how a native speaker would say it?

I've found a possibly proverb:

  • You're wise after the event.

In my opinion it makes sense and it is exactly what I am going to say, but the problem is that based on this link it is mainly BrE and I need to know whether is works in AmE too. If not, then please someone let me know how an American would convey the same thing?

  • 1
    It would be somewhat unusual for a native speaker (of AmE or BrE) to pepper a conversation with proverbs. See definition #2 here: en.oxforddictionaries.com/definition/polonian
    – TimR
    Commented Feb 11, 2017 at 13:48
  • A common phrase on the "oh, I knew it." side would be "I knew that. I was just testing you."
    – user3169
    Commented Feb 12, 2017 at 0:59
  • 1
    Your question would be clearer is you quoted an actual conversation describing the issue at hand.
    – user3169
    Commented Feb 12, 2017 at 1:01
  • All right @user3169. I will edit my thread.
    – A-friend
    Commented Feb 12, 2017 at 3:56

1 Answer 1


In AmE we say

Hindsight is 20/20.

20/20 is how normal unimpaired vision is characterized by the optometrist: you see at a distance of 20 feet what should be seen at that distance by a person whose vision does not need to be corrected with eyeglasses.

  • Just telling "Hindsight is 20/20" without any prefix or suffix would imply the message in my question in both cases I provided @TRomano?
    – A-friend
    Commented Feb 11, 2017 at 15:38
  • 1
    Your examples are quite different. The first is a clear example of hindsight.With the second, it's not quite clear what is going on. Is the person lying, claiming to have known the answer when they did not? Or is the person saying that they had not quite understood what was being asked, and now that they do, it was indeed something they knew all along?
    – TimR
    Commented Feb 11, 2017 at 15:57
  • Well, perhaps the second is a bit foggy. Let me explain it more. In my language when someone is claiming that they could remember or somehow find out the response to the question after knowing the answer OR when they are lying that they knew the answer and they just couldn't (remember it / find it out) it in time, this proverb / idiom can be used @TRomano.
    – A-friend
    Commented Feb 11, 2017 at 16:04

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .