
Verbe régulier : happen -  happened - happened
Traduction française : arriver - se passer 
Forme simple | Forme en V-ing | 
| - - it'd happen - - -  | - - it'd be happening - - -  | 
Perfect | Perfect en V-ing | 
| - - it should've happened - - -  | - - it should've been happening - - -  | 
Forme simple | Forme en V-ing | 
| - - it shouldn't happen - - -  | - - it shouldn't be happening - - -  | 
Perfect | Perfect en V-ing | 
| - - it shouldn't have happened - - -  | - - it shouldn't have been happening - - -  | 
Forme simple | Forme en V-ing | 
| - - should it happen? - - -  | - - should it be happening? - - -  | 
Perfect | Perfect en V-ing | 
| - - should it have happened? - - -  | - - should it have been happening? - - -  | 
Forme simple | Forme en V-ing | 
| - - shouldn't it happen? - - -  | - - shouldn't it be happening? - - -  | 
Perfect | Perfect en V-ing | 
| - - shouldn't it have happened? - - -  | - - shouldn't it have been happening? - - -  |