Wish or If Only clause can be used expresses in two different times. In present or future, we use it to expresses our desires, wishes. In other words, we want something to be different from now. In past, we use it to expresses our regrets. Both of them are talking about unreal/imaginary situations.
What’s the difference between Wish and If Only?
There is no big difference between Wish and if only in meaning. They are mostly interchangeable. “If only” is used to express a more resigned (you think that it won’t happen) situation. On the other hand “wish” shows a stronger (you believe it may happen) and more personal preference on the situation.
If only he had a car. He would be very happy. (The speaker thinks it’s almost impossible. It’s more emphatic.)
I wish he had a car. Who knows? He might get a car one day. (The speaker hopes that he had a car one day.)
What are the forms?
There are two forms. You can make a wish for the present time being and also for the past time as well.
|Present Wishes||Past Wishes|
wish/wishes + past simple or past continuous
I wish I had a bigger car.
I wish I was drinking tea now.
wish/wishes + past perfect
He wishes he'd finished the homework yesterday.