Who would have thought

[Tdol]

[Trance Freak]

Conditional 3:
If it would happen, one would have thought about it.
->Who would have thought it would happen?

[meskete]

This one is:
If it HAD happened...
However, I don't see the connection.

[Mzungu39]

Conditional 3:
If it would happen, one would have thought about it.
This one should be: If it had happened, we would have thought...

->Who would have thought it would happen?

That's not a conditional, there's no condition here. It's a subordinate clause (functioning as direct object).
Who would have thought (that) it would happen?

[Trance Freak]

I know that the common structure is "If it had happened," but the thing is that some of the grammar books say that "If it had happened, we would have thought about it," is as correct as "If it would happen, one would have thought about it."

Conditional is not just restricted to the "have."
Conditional 3:
I would if I could. (No "had") --> If I could cook, I would have done it.
If I would win the lottery, I would have told you.
If I had won ....
Not to mention the case of "wish."

[Mzungu39]

[QUOTE=Trance Freak;578733]I know that the common structure is "If it had happened," but the thing is that some of the grammar books say that "If it had happened, we would have thought about it," is as correct as "If it would happen, one would have thought about it."
I don't agree. Which grammar book says that?


Conditional is not just restricted to the "have."
It's not, there are certain rules of how to express a condition...
Conditional 3:
I would if I could. (No "had") --> If I could cook, I would have done it.
Modal verbs (could in this case) can be used in conditionals.

If I would win the lottery, I would have told you. This is not OK, will/would is usually not used in a conditional clause, it's possiblewhen you want to express willingness.
If I had won ....
Not to mention the case of "wish."
Wishes in the present are usually expressed with the Past tense and wishes in the past with the Past Perfect.

[ian_k]

I think both can be correct depending on which probability contrasting the reality the speaker is stating.

In addition, the original premises may as well have been either
"It would happen." vs "It would have happened."
or
"It will happen." vs "It will have happened."

If we substitute would with could, the reasoning will be easier to follow, (i think )
For example:
Who would have thought that killing an innocent child could happen in this small conservative town.
But who would have thought that the killing could have happened in broad daylight.

[ishana]

Help me please. I'm totally confused.

[Sukhdeepak]

Sometime would is used in place of 'used to'. Who would have thought means somebody had thought over it.

[Tdol]

I don't see that the sentence implies that they had thought repeatedly or ceased to do so, though, so I am not sure that you can substitute 'would have thought' for 'used to think' here without changing the meaning or expanding on the context.