Regular verb: thunder - thundered - thundered
Simple form | V-ing form |
- - it must thunder - - - | - - it must be thundering - - - |
Perfect | V-ing perfect |
- - it must have thundered - - - | - - it must have been thundering - - - |
Simple form | V-ing form |
- - it mustn't thunder - - - | - - it mustn't be thundering - - - |
Perfect | V-ing perfect |
- - it mustn't have thundered - - - | - - it mustn't have been thundering - - - |
Simple form | V-ing form |
- - must it thunder? - - - | - - must it be thundering? - - - |
Perfect | V-ing perfect |
- - must it have thundered? - - - | - - must it have been thundering? - - - |
Simple form | V-ing form |
- - mustn't it thunder? - - - | - - mustn't it be thundering? - - - |
Perfect | V-ing perfect |
- - mustn't it have thundered? - - - | - - mustn't it have been thundering? - - - |