
Regular verb: seem - seemed - seemed
Simple form | V-ing form | 
| - - it may seem - - -  | - - it may be seeming - - -  | 
Perfect | V-ing perfect | 
| - - it may have seemed - - -  | - - it may have been seeming - - -  | 
Simple form | V-ing form | 
| - - it mayn't seem - - -  | - - it mayn't be seeming - - -  | 
Perfect | V-ing perfect | 
| - - it mayn't have seemed - - -  | - - it mayn't have been seeming - - -  | 
Simple form | V-ing form | 
| - - may it seem? - - -  | - - may it be seeming? - - -  | 
Perfect | V-ing perfect | 
| - - may it have seemed? - - -  | - - may it have been seeming? - - -  | 
Simple form | V-ing form | 
| - - mayn't it seem? - - -  | - - mayn't it be seeming? - - -  | 
Perfect | V-ing perfect | 
| - - mayn't it have seemed? - - -  | - - mayn't it have been seeming? - - -  |