I can retighten you can retighten he can retighten we can retighten you can retighten they can retighten
V-ing form
I can be retightening you can be retightening he can be retightening we can be retightening you can be retightening they can be retightening
Perfect
I can have retightened you can have retightened he can have retightened we can have retightened you can have retightened they can have retightened
V-ing perfect
I can have been retightening you can have been retightening he can have been retightening we can have been retightening you can have been retightening they can have been retightening
Negation
Simple form
I can't retighten you can't retighten he can't retighten we can't retighten you can't retighten they can't retighten
V-ing form
I can't be retightening you can't be retightening he can't be retightening we can't be retightening you can't be retightening they can't be retightening
Perfect
I can't have retightened you can't have retightened he can't have retightened we can't have retightened you can't have retightened they can't have retightened
V-ing perfect
I can't have been retightening you can't have been retightening he can't have been retightening we can't have been retightening you can't have been retightening they can't have been retightening
Interrogative form
Simple form
can I retighten? can you retighten? can he retighten? can we retighten? can you retighten? can they retighten?
V-ing form
can I be retightening? can you be retightening? can he be retightening? can we be retightening? can you be retightening? can they be retightening?
Perfect
can I have retightened? can you have retightened? can he have retightened? can we have retightened? can you have retightened? can they have retightened?
V-ing perfect
can I have been retightening? can you have been retightening? can he have been retightening? can we have been retightening? can you have been retightening? can they have been retightening?
Interro-negative form
Simple form
can't I retighten? can't you retighten? can't he retighten? can't we retighten? can't you retighten? can't they retighten?
V-ing form
can't I be retightening? can't you be retightening? can't he be retightening? can't we be retightening? can't you be retightening? can't they be retightening?
Perfect
can't I have retightened? can't you have retightened? can't he have retightened? can't we have retightened? can't you have retightened? can't they have retightened?
V-ing perfect
can't I have been retightening? can't you have been retightening? can't he have been retightening? can't we have been retightening? can't you have been retightening? can't they have been retightening?