Zero, First, Second and Third Conditional
Zero conditionals talk about things that are always true (e.g. scientific facts, habits)
In zero conditional both verbs are in the present simple:
If I get hiccups, I hold my breath or drink a cup of water.
If you freeze water, it turns into ice.
If you boil water, it evaporates.
First Conditional = likely/possible
If + present simple, will + infinitive (future simple)
If I see a snake, I will scream (I travel across India, that's why it is possible)
If all the political parties work together, there won't be so many problems.
If you see a black cat, you'll have good luck.
If you break a mirror, you'll have seven years' bad luck.
If you walk under a ladder, you'll be unlucky.
If you cook dinner, I'll do the washing up.
If you do the washing, I'll do the ironing.
If you wash the car, I'll do the vacuuming.
If you watch too much television, you'll get square eyeballs.
If you don't do your homework, you won't pass your exams.
Second Conditional = unlikely, impossible
If + past simple, would + infinitive
If I saw a shake in my bed, I would scream (very unlikely situation)
If I won the lottery I would give up my job immediately.
(I think it is unlikely).
If I were to win the lottery, I would buy myself a house.
were to + infinitive is used to make a statement sound even more unlikely
If I were a rich woman, I would travel the world.
Third Conditional and Inversion = regrets and alternative in the past
If + past perfect simple/continuous, would/might/could + have + past participle
If I had booked tickets earlier, I would have bought them cheaper.
Had I booked tickets earlier, I would have bought them cheaper. (inversion - more formal)
If I had studied harder, I would have passed my exam.