Would the above sentence sound natural? If not, what would be the modification?
This has been tackled before, in the Behave as if it was or it were thread, but I've noticed an inconsistency in my own usages.
[A] "I wouldn't do this if it weren't compulsory" uses the irrealis construction.
[B] "I wouldn't do this if it wasn't compulsory" uses the indicative.
I'm happy with either alternative, and both ACGEL and CGEL say both are widely used, with [A] being the more formal.
However, I'd stick with
[C] "If I were were the manager" most of the time,
[E] "If I were you"
all the time.
You could write it as following, using would/had been : "I wouldn't do it, if it hadn't been compulsory."
This answer is grammatically incorrect, as it mixes the present and past unreal conditionals.
The past unreal uses past perfect tense in the dependent clause, and would + have + past participle in the independent clause. Ex: I wouldn't have done it if it hadn't been compulsory.
The present unreal uses the past tense in the dependent clause and would + present tense in the independent clause. Ex: I wouldn't do it if it weren't compulsory.
However as we English speakers tend to butcher the conditionals (here in Rhode Island, it's "I wouldn't of done it if it wouldn't of been compulsory"),pragmatically, this mixed conditional sentence is ok, as almost anyone would understand the message the speaker wanted to convey.