The four conditionals
FoundationEach type pairs one tense in the if-clause with one form in the main clause. The pairing is fixed.
The whole subtopic is these four rows. Almost every question is a sentence with one half given and the other half as the blank.
| Type | If-clause | Main clause |
|---|---|---|
| Zero — general truth | present | present |
| First — likely future | present | will + verb |
| Second — unlikely or unreal now | past | would + verb |
| Third — impossible, past | had + past participle | would have + past participle |