It's normal that we answer the question:
What if rainforests disappeared?
- If the rainforests should disappear, then we would die.
Or that we put the question:
Should the rainf. disappear, what would happen then?
But what about a 3rd conditional. Can we use Should also here?
Look, is it correct to say:
IF the rainf. should have disappeared in the stone age, what would have happened then?
And to answer:
IF the rainf. should have disappeared, then we would have all died in the stone age.
I'd like to put the same question about "were to".
It is correct to say:
Were the rainforests to disappear, what would happen then?
And to answer:
Were the rainforests to disappear, then we would all die.
But is it correct to say:
Had the rainforests been to disappear in the stone age, what would our ancestors have done then?
And to answer:
Had the rainforests been to disappear in the stone age, our ancestors would have all died, and we wouldn't be here now.
Finally, about the structure "Imagine +Gerunde":
It is correct to say:
Imagine the rainforests disappearing / being to disappear, what would happen then?
And to answer:
Imaging the rainforests disappearing / being to disappear, then we would all die.
But is it correct to say:
Imagine the rainforests having disappeared/ having been to disappear in the stone age, what would our ancestors have done then?
And to answer:
Imagine the rainforests having disappeared / having been to disappear in the stone age, our ancestors would have all died, and we wouldn't be here now.
What if rainforests disappeared?
- If the rainforests should disappear, then we would die.
Or that we put the question:
Should the rainf. disappear, what would happen then?
But what about a 3rd conditional. Can we use Should also here?
Look, is it correct to say:
IF the rainf. should have disappeared in the stone age, what would have happened then?
And to answer:
IF the rainf. should have disappeared, then we would have all died in the stone age.
I'd like to put the same question about "were to".
It is correct to say:
Were the rainforests to disappear, what would happen then?
And to answer:
Were the rainforests to disappear, then we would all die.
But is it correct to say:
Had the rainforests been to disappear in the stone age, what would our ancestors have done then?
And to answer:
Had the rainforests been to disappear in the stone age, our ancestors would have all died, and we wouldn't be here now.
Finally, about the structure "Imagine +Gerunde":
It is correct to say:
Imagine the rainforests disappearing / being to disappear, what would happen then?
And to answer:
Imaging the rainforests disappearing / being to disappear, then we would all die.
But is it correct to say:
Imagine the rainforests having disappeared/ having been to disappear in the stone age, what would our ancestors have done then?
And to answer:
Imagine the rainforests having disappeared / having been to disappear in the stone age, our ancestors would have all died, and we wouldn't be here now.