would have been doing

[tufguy]

Hi guys,

If we want to say that something used to happen in the past but we are not sure so do we need to use "Would have been doing" , like "Dinosaur would have been migrating from here to there" is this right if not what would be the correct form?

 

[HugoJ]

Would have been doing is a conditional perfect progressive, It refers to a past event that might have occured but it's now too late. For ex : The dinosaurs would have been migrating from here to there if they hadn't been destroyed by a meteorite.

I'm not a teacher.

 

[bhaisahab]

Would have been doing is a conditional perfect progressive, It refers to a past event that might have occured but it's now too late. For ex : The dinosaurs would have been migrating from here to there if they hadn't been destroyed by a meteorite.

I'm not a teacher.

Not necessarily, Hugo. It could be "Dinosaurs would have been migrating at that time". Here we are talking about something that could have happened.

 

[Matthew Wai]

Here we are talking about something that could have happened.

Why not use "might" instead of "would" here?

 

[Raymott]

Why not use "might" instead of "would" here?

"Would have been migrating" is an inference. For example, "In my theory, the dinosaurs would have migrating at that time." I don't want to say "they might have been migrating" (they might have doing almost anything). From the evidence I have, I want to assert that they had been migrating. Of course, my theory could be wrong.

 

[tufguy]

So I think we can say "He would have been using school bus when he was in the 7th std(here I am just estimating I am not sure of it) we don't want to use "Had done" clause.

 

[Raymott]

So I think we can say "He would have been using school bus when he was in the 7th std(here I am just estimating I am not sure of it) we don't want to use "Had done" clause.

That's right. You can't say "He had been using the bus". That's too definite. But you want to say more than "He might have been using the bus." You could say, "He must have been using the bus." if you have good evidence that there was no other way he could have got to school. But "must have" is too strong for the dinosaur claim.

 

[tufguy]

Ok but the "Would have done" is also acceptable.

 

[tufguy]

Is "would have been going" is acceptable here, or we can also use "may" instead of "would" but can we ise "may have done" for the dinosaur incidents?

 

[Raymott]

Is "would have been going" is acceptable here, or we can also use "may" instead of "would" but can we ise "may have done" for the dinosaur incidents?

No. You'd use "might have done" for the past, and as I explained, you want to say more than that the dinosaurs "might have been migrating". The claim is that they "would have been migrating".
You might understand this better if you studied the modal verbs from some grammar source. It's really much more efficient than trying to build up an understanding from isolated examples only.