конспект

express a general truth or a scientific fact
If\When + Present Simple --- Present Simple

If we heat ice, it melts.
If you freeze water, it turns into ice.
If I am late, my father takes me to school.
When I am late, my father takes me to school.

express real or probable situations in the present or future
If +Present Simple --- Future Simple (will + V)

If the weather is fine, we will go for a walk.
She will get the job if she does well at the interview.

express unreal situations in the present or future
If + Past Simple/Continuous --- would + V
If I had much money, I would buy a car.
I would help you if I had more free time.

If I were you, I would stay in.

express unreal situations in the past (regret)
If + Past Perfect/Continuous --- would + V3
If I had studied harder, I would have passed the exams.
If I had known his mobile number, I would have called him.

express a wish in the present
I wish I were on holiday. (but I’m not)
express regret in the past
I wish you had been more careful. (but you weren’t)
express a wish for a situation to change
I wish he would stop lying. (but I don’t think he will)

If only is more emphatic or more dramatic.