First Conditional � If clause present tense; main clause future tense � Used to talk about the consequence of a possible action: �If I write my essay this afternoon, I will have time to go out tonight. (It is still morning, and is quite possible that I will do this. )
Second Conditional � If clause past simple main clause conditional tense � Used to talk about the consequence of a hypothetical action: �If I wrote my essay this afternoon, I would have time to go out tonight. (It is still morning, but I think it is less likely that I will do this. )
Third Conditional � If clause past perfect main clause conditional perfect tense � Used to talk about the possible consequence of an action that did not happen: �If I had written my essay this afternoon, I would have had time to out tonight. (It is now evening, and I haven’t written my essay; it is now impossible for me to go out. )
Zero Conditional � Sometimes sentences with if express certainty rather than possibility. The ZERO CONDITIONAL is used to talk about something that is always true, or that was always true in the past: �If you mix blue and red, you get purple. (present simple in both parts of the sentence) �If I asked her to come with us, she always said no. (past simple in both parts of the sentence)