I can flatten you can flatten he can flatten we can flatten you can flatten they can flatten
V-ing form
I can be flattening you can be flattening he can be flattening we can be flattening you can be flattening they can be flattening
Perfect
I can have flattened you can have flattened he can have flattened we can have flattened you can have flattened they can have flattened
V-ing perfect
I can have been flattening you can have been flattening he can have been flattening we can have been flattening you can have been flattening they can have been flattening
Negation
Simple form
I can't flatten you can't flatten he can't flatten we can't flatten you can't flatten they can't flatten
V-ing form
I can't be flattening you can't be flattening he can't be flattening we can't be flattening you can't be flattening they can't be flattening
Perfect
I can't have flattened you can't have flattened he can't have flattened we can't have flattened you can't have flattened they can't have flattened
V-ing perfect
I can't have been flattening you can't have been flattening he can't have been flattening we can't have been flattening you can't have been flattening they can't have been flattening
Interrogative form
Simple form
can I flatten? can you flatten? can he flatten? can we flatten? can you flatten? can they flatten?
V-ing form
can I be flattening? can you be flattening? can he be flattening? can we be flattening? can you be flattening? can they be flattening?
Perfect
can I have flattened? can you have flattened? can he have flattened? can we have flattened? can you have flattened? can they have flattened?
V-ing perfect
can I have been flattening? can you have been flattening? can he have been flattening? can we have been flattening? can you have been flattening? can they have been flattening?
Interro-negative form
Simple form
can't I flatten? can't you flatten? can't he flatten? can't we flatten? can't you flatten? can't they flatten?
V-ing form
can't I be flattening? can't you be flattening? can't he be flattening? can't we be flattening? can't you be flattening? can't they be flattening?
Perfect
can't I have flattened? can't you have flattened? can't he have flattened? can't we have flattened? can't you have flattened? can't they have flattened?
V-ing perfect
can't I have been flattening? can't you have been flattening? can't he have been flattening? can't we have been flattening? can't you have been flattening? can't they have been flattening?