
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 oughtn't to snow - - -  | - - it oughtn't to be snowing - - -  | 
Perfect | V-ing perfect | 
| - - it oughtn't to have snowed - - -  | - - it oughtn't 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 | 
| - - oughtn't it to snow? - - -  | - - oughtn't it to be snowing? - - -  | 
Perfect | V-ing perfect | 
| - - oughtn't it to have snowed? - - -  | - - oughtn't it to have been snowing? - - -  |