Can we use the conjunctions "provided", "unless", "as long as" with all the tenses with which we use "if" ?

[matar0]

Can we use the conjunctions "provided", "unless", "as long as" with all the tenses with which we use "if" ?
For instance, are the following sentences correct?
If there were an earthquake, we would die. ;
Unless there were an earthquake we wouldn’t die ;
Provided there weren’t / As long as there weren’t an earthquake we wouldn’t die
What about the 3rd conditional sentence?
If there had been an earthquake, we would have died. ;
Unless there had been an earthquake we wouldn’t have died ;
Provided there hadn't been / As long as there hadn't been an earthquake we wouldn’t have died.

Thanks much

 

[MissFit]

All of your examples sound OK to me grammatically, but I can't imagine ever having a need to use some of them--especially that last one. I think that you are probably correct, that those phrases can be used with all of the same tenses as if. The key is to make sure that the verbs in the two clauses are compatible--and you seem to have matched them correctly.

 

[petereid]

Hi
"If" very often takes the "subjunctive", as you have done in the first phrase.
The others don't normally.