Zero
If you (heat) water, it (boil).
<p>If you heat water, it boils.</p>
If you (heat) ice, it (melt).
If you heat ice, it melts.
If she (have) more money, she (travel) around the world.
If she had more money, she would travel around the world.
If they (go) to bed early, they (not/wake) up late.
If they had gone to bed early, they would not have woken up late.
If plants (not get) water, they (wilt).
If plants don't get water, they wilt.
If he (come), I (be) surprised.
If he comes, I will be surprised.
If we (live) closer, we (see) each other more often.
If we lived closer, we would see each other more often.
If he (not/fall down) the stairs, he (not/twist) his ankle.
If he hadn't fallen down the stairs, he wouldn't have twisted his ankle.
If the sun (set), it (get) dark.
If the sun sets, it gets dark.
If we (not/see) each other tomorrow, we (see) each other next week.
If we don't see each other tomorrow, we will see each other next week.
If she (not/be) always so late, she (be) promoted.
If she was not always so late, she would be promoted.
If she (study) she (pass) the exam.
If she had studied she would have passed the exam.
If I (drink) coffee at night, I (not sleep) well.
If I drink coffee at night, I don't sleep well.
If they (study / not) harder, they (pass / not) the exam.
If they don't study harder, they won't pass the exam.
If he (have) more time, he (learn) how to play the guitar.
If he had more time, he would learn how to play the guitar.
If we (arrive) earlier, we (see) John.
If we had arrived earlier, we would have seen John.
Alex (go) to London next week if he (get) a cheap flight.
Alex will go to London next week if he gets a cheap flight.
I (marry) someone famous if I (be) a movie star.
I would marry someone famous if I were a movie star.