I can better you can better he can better we can better you can better they can better
V-ing form
I can be bettering you can be bettering he can be bettering we can be bettering you can be bettering they can be bettering
Perfect
I can have bettered you can have bettered he can have bettered we can have bettered you can have bettered they can have bettered
V-ing perfect
I can have been bettering you can have been bettering he can have been bettering we can have been bettering you can have been bettering they can have been bettering
Negation
Simple form
I can't better you can't better he can't better we can't better you can't better they can't better
V-ing form
I can't be bettering you can't be bettering he can't be bettering we can't be bettering you can't be bettering they can't be bettering
Perfect
I can't have bettered you can't have bettered he can't have bettered we can't have bettered you can't have bettered they can't have bettered
V-ing perfect
I can't have been bettering you can't have been bettering he can't have been bettering we can't have been bettering you can't have been bettering they can't have been bettering
Interrogative form
Simple form
can I better? can you better? can he better? can we better? can you better? can they better?
V-ing form
can I be bettering? can you be bettering? can he be bettering? can we be bettering? can you be bettering? can they be bettering?
Perfect
can I have bettered? can you have bettered? can he have bettered? can we have bettered? can you have bettered? can they have bettered?
V-ing perfect
can I have been bettering? can you have been bettering? can he have been bettering? can we have been bettering? can you have been bettering? can they have been bettering?
Interro-negative form
Simple form
can't I better? can't you better? can't he better? can't we better? can't you better? can't they better?
V-ing form
can't I be bettering? can't you be bettering? can't he be bettering? can't we be bettering? can't you be bettering? can't they be bettering?
Perfect
can't I have bettered? can't you have bettered? can't he have bettered? can't we have bettered? can't you have bettered? can't they have bettered?
V-ing perfect
can't I have been bettering? can't you have been bettering? can't he have been bettering? can't we have been bettering? can't you have been bettering? can't they have been bettering?