虚拟语气的搭配都是固定的.你的你的主句是If it were,那从句就只能是would+动词原形.
与..事实相反 If从句 主句
过去 Had done Would have done
现在 Were/did Would* do
将来 Should do/were/were to do Would* do
例句：If there hadn’t been much rain in spring, we would have had a good harvest now. [过去]
If he smoked less, his cough might be well soon. [现在]
If the lecturer should be late, you would have to make a speech first. [将来]