
Regular verb: snow - snowed - snowed
| Simple form | V-ing form | 
| - - it ought to snow - - - | - - it ought to be snowing - - - | 
| Perfect | V-ing perfect | 
| - - it ought to have snowed - - - | - - it ought to have been snowing - - - | 
| Simple form | V-ing form | 
| - - it ought not to snow - - - | - - it ought not to snowing - - - | 
| Perfect | V-ing perfect | 
| - - it ought not to have snowed - - - | - - it ought not to have been snowing - - - | 
| Simple form | V-ing form | 
| - - ought to it snow? - - - | - - ought to it be snowing? - - - | 
| Perfect | V-ing perfect | 
| - - ought to it have snowed? - - - | - - ought to it have been snowing? - - - | 
| Simple form | V-ing form | 
| - - ought it not to snow? - - - | - - ought it not to be snowing? - - - | 
| Perfect | V-ing perfect | 
| - - ought it not to have snowed? - - - | - - ought it not to have been snowing? - - - |