I can flatten you can flatten she can flatten we can flatten you can flatten they can flatten
V-ing form
I can be flattening you can be flattening she can be flattening we can be flattening you can be flattening they can be flattening
Perfect
I can have flattened you can have flattened she 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 she 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 she 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 she 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 she 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 she 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 she flatten? can we flatten? can you flatten? can they flatten?
V-ing form
can I be flattening? can you be flattening? can she be flattening? can we be flattening? can you be flattening? can they be flattening?
Perfect
can I have flattened? can you have flattened? can she 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 she 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 she 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 she 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 she 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 she have been flattening? can't we have been flattening? can't you have been flattening? can't they have been flattening?