
Regular verb: rain - rained - rained
Simple form | V-ing form | 
| - - it'd rain - - -  | - - it'd be raining - - -  | 
Perfect | V-ing perfect | 
| - - it should've rained - - -  | - - it should've been raining - - -  | 
Simple form | V-ing form | 
| - - it shouldn't rain - - -  | - - it shouldn't be raining - - -  | 
Perfect | V-ing perfect | 
| - - it shouldn't have rained - - -  | - - it shouldn't have been raining - - -  | 
Simple form | V-ing form | 
| - - should it rain? - - -  | - - should it be raining? - - -  | 
Perfect | V-ing perfect | 
| - - should it have rained? - - -  | - - should it have been raining? - - -  | 
Simple form | V-ing form | 
| - - shouldn't it rain? - - -  | - - shouldn't it be raining? - - -  | 
Perfect | V-ing perfect | 
| - - shouldn't it have rained? - - -  | - - shouldn't it have been raining? - - -  |