I can brighten you can brighten he can brighten we can brighten you can brighten they can brighten
V-ing form
I can be brightening you can be brightening he can be brightening we can be brightening you can be brightening they can be brightening
Perfect
I can have brightened you can have brightened he can have brightened we can have brightened you can have brightened they can have brightened
V-ing perfect
I can have been brightening you can have been brightening he can have been brightening we can have been brightening you can have been brightening they can have been brightening
Negation
Simple form
I can't brighten you can't brighten he can't brighten we can't brighten you can't brighten they can't brighten
V-ing form
I can't be brightening you can't be brightening he can't be brightening we can't be brightening you can't be brightening they can't be brightening
Perfect
I can't have brightened you can't have brightened he can't have brightened we can't have brightened you can't have brightened they can't have brightened
V-ing perfect
I can't have been brightening you can't have been brightening he can't have been brightening we can't have been brightening you can't have been brightening they can't have been brightening
Interrogative form
Simple form
can I brighten? can you brighten? can he brighten? can we brighten? can you brighten? can they brighten?
V-ing form
can I be brightening? can you be brightening? can he be brightening? can we be brightening? can you be brightening? can they be brightening?
Perfect
can I have brightened? can you have brightened? can he have brightened? can we have brightened? can you have brightened? can they have brightened?
V-ing perfect
can I have been brightening? can you have been brightening? can he have been brightening? can we have been brightening? can you have been brightening? can they have been brightening?
Interro-negative form
Simple form
can't I brighten? can't you brighten? can't he brighten? can't we brighten? can't you brighten? can't they brighten?
V-ing form
can't I be brightening? can't you be brightening? can't he be brightening? can't we be brightening? can't you be brightening? can't they be brightening?
Perfect
can't I have brightened? can't you have brightened? can't he have brightened? can't we have brightened? can't you have brightened? can't they have brightened?
V-ing perfect
can't I have been brightening? can't you have been brightening? can't he have been brightening? can't we have been brightening? can't you have been brightening? can't they have been brightening?