I can curb you can curb she can curb we can curb you can curb they can curb
V-ing form
I can be curbing you can be curbing she can be curbing we can be curbing you can be curbing they can be curbing
Perfect
I can have curbed you can have curbed she can have curbed we can have curbed you can have curbed they can have curbed
V-ing perfect
I can have been curbing you can have been curbing she can have been curbing we can have been curbing you can have been curbing they can have been curbing
Negation
Simple form
I can't curb you can't curb she can't curb we can't curb you can't curb they can't curb
V-ing form
I can't be curbing you can't be curbing she can't be curbing we can't be curbing you can't be curbing they can't be curbing
Perfect
I can't have curbed you can't have curbed she can't have curbed we can't have curbed you can't have curbed they can't have curbed
V-ing perfect
I can't have been curbing you can't have been curbing she can't have been curbing we can't have been curbing you can't have been curbing they can't have been curbing
Interrogative form
Simple form
can I curb? can you curb? can she curb? can we curb? can you curb? can they curb?
V-ing form
can I be curbing? can you be curbing? can she be curbing? can we be curbing? can you be curbing? can they be curbing?
Perfect
can I have curbed? can you have curbed? can she have curbed? can we have curbed? can you have curbed? can they have curbed?
V-ing perfect
can I have been curbing? can you have been curbing? can she have been curbing? can we have been curbing? can you have been curbing? can they have been curbing?
Interro-negative form
Simple form
can't I curb? can't you curb? can't she curb? can't we curb? can't you curb? can't they curb?
V-ing form
can't I be curbing? can't you be curbing? can't she be curbing? can't we be curbing? can't you be curbing? can't they be curbing?
Perfect
can't I have curbed? can't you have curbed? can't she have curbed? can't we have curbed? can't you have curbed? can't they have curbed?
V-ing perfect
can't I have been curbing? can't you have been curbing? can't she have been curbing? can't we have been curbing? can't you have been curbing? can't they have been curbing?