Updated: Jun 28, 2020
1st - If I see her, I'll tell her
Possible situation= Present Simple------will + main verb
2nd- If I were taller, I'd be a basketball player
Impossible or unlikely= Past Simple-------would + main verb
3rd- If I had known you were in hospital, I'd have visited you.
Past Perfect-------would + present perfect
The first 2 conditionals are referring to the present. The only difference is that in the 1st example, the if clause is possible to happen.
Notice how impossible the 2nd conditional sounds.
The 3rd conditional is the only one that refers to the past (both parts of the sentence). I didn't know you were in hospital, so I didn't visit you. Nothing can change now...I can only apologise.
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