| Form | Example | |
|---|---|---|
| Six types | zero · 1st · 2nd · 3rd · mixed A · mixed B | all combinations of time |
| Inversion | Had I / Were I / Should you / Were it not for | formal register, drops "if" |
| Alternatives | provided that / as long as / unless / in case | precise shades of condition |
| Wish / if only | + past / + past perfect / + would | wish I knew / wish I had studied |
| It's (high) time | + past simple | it's time you left |