Is it "What could have happen" or "What could have happened"?

[CeliVega]

I am confuse about which one is the correct. Technically speaking the "what" never happen, so should it be in present tense? Or should past tense be used because we assumed the "what" has already happened? Same thing with "What might have happen" or "What might have happened". Which one is the correct one?

Thanks in advance for the replies everyone!

[Denis Hard]

It doesn't matter. If something didn't happen, we can still speculate. . .mull over what could have happened if. . .

So:

"What could have happened" is correct.

[Daimashin]

What could have happened can only go one way and that is to speculate the consequences. The effect to the cause so when we use "what could have happened" it means that we're referring to something that has happened but in a different outcome. It's in the past so the answer is "what could have happened if ..."

[SmartPea85]

It should be "happened" because you are still asking about an event that did or did not happen in the past, thus the "happen" should be in the past tense. If you are speculating about something in the future or present tense, you might say something like "What would happen if...?"

[fredkawig]

What could have happened is the correct usage, you can immediately distinguish wrong grammar from one which is correct. It is in a conditional perfect tense according to this site http://www.englisch-hilfen.de/en/grammar/english_tenses.htm

[g2narat]

Ah well, looks like this question has already been answered. Here's an explanation that might make things easier to remember though. It should be "What could have happened" because you are talking about something in the past. If that thing had happened then it would have already happened, so it's only natural to use past tense. It's much easier to think of it that way instead of talking about grammar rules in my opinion.

[CeliVega]

Alrighty then!

Guess I got my question perfectly answer, "What could have happened" is the correct phrase!

Thanks again everyone!

"What could have happened if I didn't stumbled upon this place......"

That's how we use the phrase right XD

[003]

'What could have happened' is the correct one because it is preceded by the auxiliary verb have.

It would be the same as 'should have happened', 'must have happened' and 'would have happened'.

[foodietr]

What could happen is correct, adding a have sound weird and is incorrect.

The latter is correct.

[AureliaeLacrimae]

  On 5/13/2014 at 9:28 AM, CeliVega said:

Alrighty then!

Guess I got my question perfectly answer, "What could have happened" is the correct phrase!

Thanks again everyone!

"What could have happened if I didn't stumbled upon this place......"

That's how we use the phrase right XD

Although I'd rather put ''What could have happened if I hadn't stumbled upon this place...'' to make it a clear third conditional - however, mixed conditional is fine as well. The clear third conditional is more of a textbook example, though.

Modal verbs must be followed by BARE INFINITIVE - that is, infinitive without to:

may happen, will go, can play, could see

They can also be followed by PAST INFINITIVE:

may have done, could have been, would have left

PAST INFINITIVE form:

have + past participle [3rd column form for irregular verbs/-ed for regular]

(always have!! even if the subject is 3rd person singular! it's infinitive - infinitive is non-finite and can't change)

she may have done it

not *she may has done it - you don't add present perfect, you add past infinitive

may have happen combination doesn't exist.

have is an auxiliary which contains "perfective" aspect, so it always comes with a past form, it cannot come with present form, just like be has progressive aspect as an auxiliary, so it's used in forming continuous tenses (even complex - have been doing) but can also be used in passives with past participle.

[Litnax]

Well, I'm confused about these:

" ...it was easy to root for her on every step of the way." 

"...it was easy to root for her every step of the way."

Anybody?

 

[Flowerpower]

"It was easy to root for her every step of the way."
 

I'm really bad at explaining grammar, but that one is the only way I've ever heard it. 

[KIO5NN8C7DEB15AYGM0U]

This post has been removed.

[MichaelHannigan]

"What could have happen" is incorrect because the auxiliary verb "have" needs to be followed by a verb used by the Present Perfect tense, the third form of the verb (happen/happened/happened). If you were to remove the verb "have", the tense would be correct. "What could happen?" is a Present tense used to describe a following action that did not happen yet and "What could have happened"?" is a Present Perfect tense used to describe an imaginary action that did not happen, but could have.

[sillylucy]

I think the emphasis should be on "happened" and not "happen." I always write, "What is the worst that could happen?" or "What could have happened?" as in the past tense. I hope this helps to clarify the idea that you are trying to get out.

[Baburra]

It should be what could have happened because the presence of the word "have" already points to it being in the past tense. If it were going to be used to say something about the present or the future then the word "have" would be eliminated and you could then switch the action into present tense. In this case, if the question is pertaining to the present or future then the sentence would read like "what could happen" or "what might happen".

[reverserewind]

The latter is correct, If you need my approval. It's called an unreal past, as far as I know.

[LeesaJohnson]

What could have happened is correct.

[Rishi Sehrawat]

What could have happened is correct.

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