It is rather simple to say:
Il y a for There is or There are
Il y avait for There was or There were
Il y eut for There was or There were
Il y aura for There will be
Il y aurait for There would be
But it's harder to use il y a with les temps passés as I don't have a logical model upon which to base my forming these verbal constructions.
As far as I can tell, these would be:
Il y a eu for There has been or There have been
Il y avait eu for There had been
Il y aura eu for There will have been
Il y aurait eu for There would have been
And now comes the most difficult part. How do I use il y a with pouvoir and devoir (what would be modal verbs in English) especially when used in the perfect tenses? How do I actually say:
There can be...
There could be...
There can have been...
There could have been...
There must be...
There must have been...
There had to be...
There had to have been...
There will have to be...
There will have to have been...
There would have to be...
There would have to have been...
There should be...
There should have been...
