I can whiten you can whiten he can whiten we can whiten you can whiten they can whiten
V-ing form
I can be whitening you can be whitening he can be whitening we can be whitening you can be whitening they can be whitening
Perfect
I can have whitened you can have whitened he can have whitened we can have whitened you can have whitened they can have whitened
V-ing perfect
I can have been whitening you can have been whitening he can have been whitening we can have been whitening you can have been whitening they can have been whitening
Negation
Simple form
I can't whiten you can't whiten he can't whiten we can't whiten you can't whiten they can't whiten
V-ing form
I can't be whitening you can't be whitening he can't be whitening we can't be whitening you can't be whitening they can't be whitening
Perfect
I can't have whitened you can't have whitened he can't have whitened we can't have whitened you can't have whitened they can't have whitened
V-ing perfect
I can't have been whitening you can't have been whitening he can't have been whitening we can't have been whitening you can't have been whitening they can't have been whitening
Interrogative form
Simple form
can I whiten? can you whiten? can he whiten? can we whiten? can you whiten? can they whiten?
V-ing form
can I be whitening? can you be whitening? can he be whitening? can we be whitening? can you be whitening? can they be whitening?
Perfect
can I have whitened? can you have whitened? can he have whitened? can we have whitened? can you have whitened? can they have whitened?
V-ing perfect
can I have been whitening? can you have been whitening? can he have been whitening? can we have been whitening? can you have been whitening? can they have been whitening?
Interro-negative form
Simple form
can't I whiten? can't you whiten? can't he whiten? can't we whiten? can't you whiten? can't they whiten?
V-ing form
can't I be whitening? can't you be whitening? can't he be whitening? can't we be whitening? can't you be whitening? can't they be whitening?
Perfect
can't I have whitened? can't you have whitened? can't he have whitened? can't we have whitened? can't you have whitened? can't they have whitened?
V-ing perfect
can't I have been whitening? can't you have been whitening? can't he have been whitening? can't we have been whitening? can't you have been whitening? can't they have been whitening?