I don't understand why this sentence is correct: What would you do if this happened to you?

Why use happened and not happen(s)? Is it because it's an imagined situation? Do we always have to use past tense for all imagined situation (past and future)?

  • Isn't it second conditional? if this happened to you, what would you do? /// if I understand it correctly, it's the back-shifted (?) version of what will you do if this happens to you. (I don't know grammar.)
    – Void
    Dec 6, 2020 at 9:16

1 Answer 1


You probably know that this construction is called the second conditional. In the second conditional, the condition clause (in this case, "if this happened to you") uses the past simple. It's a rule of English grammar that you just have to learn.

  • If I went to Saudi Arabia, I would speak Arabic.

You ask whether we always have to use past tense for imagined situations. I think what you mean is the past simple. In this case, the answer is no, because as you might know, the third conditional, used to talk about hypothetical events in the past, does not use the past simple:

  • If I had gone to SA, I would have spoken Arabic.

In this case, we use the past perfect (sometimes called pluperfect) in the condition clause.

I understand that it is confusing for learners to use the past simple in the condition clause of a second conditional sentence. It may help you to know that in much older forms of English and pre-English (Proto-West Germanic, etc), this was a different verb form entirely (namely the past subjunctive). Over time, sound change and other linguistic processes meant that it coalesced with the past simple. Only remnants survive today, as in If I were you...

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