
Regular verb: happen - happened - happened
| Present | Present continuous | Preterite | Preterite continuous | 
| - - it does not happen - - - | - - it is not happening - - - | - - it did not happen - - - | - - it was not happening - - - | 
| Present perfect | Present perfect continuous | Pluperfect | Pluperfect continuous | 
| - - it has not happened - - - | - - it has not been happening - - - | - - it had not happened - - - | - - it had not been happening - - - | 
| Future | Future continuous | Future perfect | Future perfect continuous | 
| - - it will not happen - - - | - - it will not be happening - - - | - - it will not have happened - - - | - - it will not have been happening - - - | 
| Present | Present continuous | Past | Past continuous | 
| - - it would not happen - - - | - - it would not be happening - - - | - - it would not have happened - - - | - - it would not have been happening - - - | 
| Infinitive | Imperative | 
| Infinitive | Imperative | ||
| to happen | - Let's not happen - | 
| Present | Past | ||
| happening | happened |