
Regular verb: rain - rained - rained
Simple form | V-ing form | 
| - - it should rain - - -  | - - it should be raining - - -  | 
Perfect | V-ing perfect | 
| - - it should have rained - - -  | - - it should have been raining - - -  | 
Simple form | V-ing form | 
| - - it should not rain - - -  | - - it should not be raining - - -  | 
Perfect | V-ing perfect | 
| - - it should not have rained - - -  | - - it should not 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 | 
| - - should it not rain? - - -  | - - should it not be raining? - - -  | 
Perfect | V-ing perfect | 
| - - should it not have rained? - - -  | - - should it not have been raining? - - -  |