文法 (10-5) - hypothetical results

You can use wish to express a desire for something to be true that is unreal or unlikely in the present or future. In the clause after wish, use the past tense of a verb (or were). That after wish is optional.

Wish in the present and future (wish that S + pt)
I wish (that) you were here. (you are not here)
I wish (that) we did not live so far apart. (we do live far apart)

Wish in the past (wish that S + had + pt)
I wish it hadn't started raining. (it started raining)
I wish the taxi had come when we called it. (the taxi did not come)

Use the past tense in the if clause to talk about something unreal or unlikely in the present or future. For the verb be, use were with all subjects. Use would/could/might + base form of the verb in the main clause to talk about the hypothetical results.

If + pt, S + would/could/might + V
I would take the bus every day if it came more frequently.

To talk about something that was unreal in the past:

If + had + pp, S + would/could/might + have pp

Jones would have won the election if the economy had been booming.