4 structures to express wishes and regrets

source: Crown Academy of English   2017年8月29日
wish + past simple
= to describe a situation in the present that we would like to be different.
We use the past simple form, but our regret is in the present.
Example: I wish I had more friends.

wish + someone / something + "would" + base form of verb
= we want someone to change their behaviour
= we want something to happen
Example: I wish you would listen.

wish + past perfect
= to describe a past situation that we regret.
Example: I wish I had gone to the concert.
We can also use "never" with a negative to emphasise our regret:
Example: I wish I had never gone to the concert.
(I went to the concert. I really regret it now.)

"if only" + past perfect
= This is another way to describe situation from the past that we regret.
If only I had passed my exams.
(I didn't pass my exams. I regret it now.)

"if only" + past perfect
wish + past perfect
The meaning of the above 2 structures is the same.
The difference is that "if only" is slightly more formal.

Past simple: https://www.youtube.com/watch?v=0Ri3Q...
Past perfect: https://www.youtube.com/watch?v=EZopc...
Verb "to be": https://www.youtube.com/watch?v=5wvzg...