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