Would have, could have, should have

[JustAlilBit]

If someone have a patience please explain how works "could have; should have; would have" somewhere I read that they express lost opportunity in the past I tried to sort out this problem, but unfortunately I didn't find information about them. While I was reading a book today I have seen them maybe one hundred time. Below is a few examples with "could have".

It's not about anything they could have done or I could have done.
It could have been from the mayor, or it could have been from a third party.
It could have been better, but it could have been worse.

 

[cereal_chick]

If someone have a patience please explain how works "could have; should have; would have"

In English, one does not say *"If someone have a patience". There are two things wrong with that sentence: you have not conjugated "to have" for third-person singular (as "someone" is neither the speaker nor the addressee and there is only one "someone" ) which would be "has". Secondly, you are saying *"a patience", which is not allowed, because "patience" is an uncountable noun – one cannot count "patiences" i.e. *"I have six patiences".

Now, onto the topic at hand,
Could have denotes an action or a state that had the possibility of happening under a certain condition in the past.
"If you had given me the book, I could have put it under the right section."
Would have denotes an action or a state (I can't think of any other way of putting this) would have happened under a certain condition in the past.
"If you had given me the book, I would have put it under the right section."
Shoud have denotes an action or a state that ought to have happened but did not.
"You should have given me the book; I would have been able to put it under the right section."

I hope that you have understood – if there is something you still need help with, just ask.

[Not a teacher]

 

[JustAlilBit]

Thanks Calis,
If I hadn't created this thread, I wouldn't have known about these things "should, would, could - have" =)

 

[5jj]

It's not about anything they could have done or I could have done.

Depending on the context, there are two possible meanings:

1. "There is the possibility that they/I had the ability to to something, but they/I did not do it."
2. 'Could' has a similar meaning to 'might', and there is the possibility that they/I did it.

It could have been from the mayor, or it could have been from a third party.
"It is possible that it came from the mayor or from a third party."

It could have been better, but it could have been worse.
"It had the potential to be better or worse than it was. That potential was not realised."