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 cannot better you cannot better he cannot better we cannot better you cannot better they cannot better
V-ing form
I cannot be bettering you cannot be bettering he cannot be bettering we cannot be bettering you cannot be bettering they cannot be bettering
Perfect
I cannot have bettered you cannot have bettered he cannot have bettered we cannot have bettered you cannot have bettered they cannot have bettered
V-ing perfect
I cannot have been bettering you cannot have been bettering he cannot have been bettering we cannot have been bettering you cannot have been bettering they cannot 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 I not better? can you not better? can he not better? can we not better? can you not better? can they not better?
V-ing form
can I not be bettering? can you not be bettering? can he not be bettering? can we not be bettering? can you not be bettering? can they not be bettering?
Perfect
can I not have bettered? can you not have bettered? can he not have bettered? can we not have bettered? can you not have bettered? can they not have bettered?
V-ing perfect
can I not have been bettering? can you not have been bettering? can he not have been bettering? can we not have been bettering? can you not have been bettering? can they not have been bettering?