There are four conditional patterns in English. Generally you learn about first and second conditionals at the pre-intermediate level. Sometimes teachers mention the zeroeth conditional. The third conditional is often saved for later because it seems complicated.
With the /'zi roʊθ/ conditional, the condition is purely a logical link, not a temporal one. It is used to talk about general truths. In other words if is equivalent to when or whenever... i.e. (à) chaque fois
- If you snooze, you lose.
- If she doesn't practice, she gets rusty.
- If I sing, it rains.
Notice that the verbs are conjugated in the standard present tense. (3rd person -s) The present progressive (be + -ing) is not common with the 0th conditional, because the 0th is outside of time.
cf. Si je joue, je gagne.
The first conditional is very common and refers to specific and sometimes unforeseen events, not generalities:
- If you wait here, I'll get the zombies for you.
- If you don't wait here, the zombies'll get you for me.
- Don't worry! They can't hear you or smell you if you stay right there.
Any present tense verb (simple, be + -ing, have + -en) can be used in the if-clause (called the protase).
One of three principal modals (can, may, or will) is used in the other clause (called the apodose).
- If you're coming to the dinner tonight, he may be there.
- I'll take the newspaper if you've finished with it.
must, shall, and should are rare in both the apodose and in the protase.
Some liberty is allowed beyond those three modals of course:
- If you wait here, the zombies should be along shortly.
- You might want to wait to buy it, if you think you can get a better deal elsewhere.
- You could wait to change cars, if you think the price will come down.
- You really must come to Vienne if you want to see some cool Roman relics.
This is very similar to French.
- Moi, si je joue, je gagnerai.
- Je vais gagner, si je joue.
In some circumstances it is also possible in English to substitute the futur proche be going to for the future modal "will", but it is far less common:
- You know that if she plays, she's going to win.
The second conditional is counter-intuitive because you use the past to speak about a potential future:
- If she had a million dollars, she wouldn't buy a yacht.
- She might be more tempted, if she had a hundred million dollars.
- You could make bills, if you had a better-paying job.
- If I had his address, I could send him the photo.
The word most associated with the 2nd conditional is irrealis, when you use the second conditional, you're saying what would or could happen under certain circumstances. in the apodose, you will find three principal modals: would, could, & might.
- If she was going to come, she would be here by now.
Again, this is very much like French:
- Si elle allait venir, elle serait déjà là.
- Si je jouais, je gagnerais.
In the apodose the three modals used in 2nd conditionals (would, could, & might) are followed by the perfect infinitive (have + -en). In the protase the verb is in the pluperfect (had + -en)
- Trust me, if she had wanted eggs, she would have asked you for some.
- Maybe I could have fixed the cellphone if I had had a way to open it up and look inside.
- J'aurais peut-être pu réparer le portable, si j'avais eu un moyen de l'ouvrir pour y regarder.
- If they'd known you were here, they might have come to say hello.
Semantics: the proposition in the protase in 3rd conditionals is not true or is not what happened. (It is said to be counterfactual.)
Again, this is like French (just simpler, because you don't have to choose between avoir & être)
- Si j'avais joué, j'aurais gagné!
Si j'aurais su, j'aurais pas venu.
- Si j'avais été toi, je me serais tu.
- If she was planning to come, she didn't tell me about it.
Conditionals with a second conditional protase and a third conditional apodose are called "hybrids" because it is really cool to have a name for everything.
- If she was planning to come, she would have been here by now.