Conditional Sentences
Conditional sentences express real or hypothetical situations and their results. There are four main types.
Zero Conditional
If + present simple, present simple (general truth)
If you heat ice, it melts.
First Conditional
If + present simple, will + base verb (real future)
If it rains, I will stay home.
Second Conditional
If + past simple, would + base verb (unreal present)
If I won the lottery, I would travel the world.
Third Conditional
If + past perfect, would have + past participle (unreal past)
If I had studied harder, I would have passed the exam.