We use type 0 to talk about general truths or facts.
If the batteries are flat, the radio doesn’t work.
Type 1 : If + present tense, will / can + infinitive.It refers to the future
We use the 1° conditional to talk about the consequences of something which may possibly happen in the future.
If you pay cash, I’ll give you a 5 % off.
Type 2 : If + past tense, would /could + infinitive. It refers to the present
We use the second conditional to talk about something which we think is unlikely to happen, to refer to a hypothetical or unreal situation. When the if clause contains the verb be, we usually use were not was, especially after I.
If I weren’t so tired, I would gladly help you.
I would gladly help you if I weren’t so tired. ( commas )
We often use the expression If I were you to give advice.
If I were you, I would take travelers’ checks.
Type 3 : If + past perfect tense, would have + past participle . It refers to the past
We use the third conditional to talk about actions or events which did not happen in the past, and the imaginary consequences.
If you had bought shares last month, you would have made a lot of money.