0 Conditional (100%)
Natural Law – This is used when something always happens:
- The grass grows if it rains and the sun shines. > Simple present, if simple present.
- If I jump up into the air, I fall back down to the ground. > If simple present, simple present.
- If you drink caffeine, your heart rate increases. > If simple present, simple present.
It is possible to substitute when for the word if in any of the zero conditional sentences. (When you are happy, you smile.)
1st Conditional (1% – 99%)
Maybe – Used when something is likely to happen. It might or might not happen, but it’s probable:
- If Emeril goes to the supermarket, he will buy some garlic. > If simple present, will + base form (future).
- If Harriet sees James, she will tell him about the meeting. > If simple present, will + base form (future).
- I‘m going to kill that kid if he comes home late again. > Going to (future) if simple present.
When you want somebody to do something based on a condition, use the 1 conditional with a command:
- If you find a purple purse, call me at this number. > If simple present, command.
- If that jerk shows up here again, tell him we need to talk. > If simple present, command.
2nd Conditional (0% – 1%)
Imaginary – This is used when something is probably not going to happen or when the situation is counterfactual (not true, not very likely):
- If we had one million dollars, we would quit our jobs. >If simple past, would + base form.
- (Truth: We don’t have one million dollars)
- If you were nice, you would give me one of your candies. >If simple past, would + base form.
- (Reality: You’re not nice)
- If Anthony knew the President, he would inform her. >If simple past, would + base form.
- (Implied: Anthony doesn’t know the President)
3rd Conditional (0%)
Impossible – Use this conditional to express regret. When you are talking about an event in the past, what happened can never be otherwise. No one can travel back in time, but we all think about changing decisions we made in the past:
- If Joan had gone to the wedding, she would have asked Ahmed to dance. > If past perfect, would have + participle.
- If you had seen the movie with us, you would have loved it. > If past perfect, would have + participle).
- If I had known then what I know now, I would’ve done things differently. > If past perfect, would have + participle.
Alternatively, sometimes making changes to the past would have an effect in the present:
- If Joan had gone to the wedding, she would be dating Amhed now. > If past perfect, would be + gerund.
- You would know what happens in the end if you had seen the movie . > Would + base form if past perfect.
- If I had known then what I know now, I would be rich, successful and happy today. > If past perfect, would be + adjective.