English verb conjugation
COULD CURB

Regular verb: curb - curbed - curbed

Affirmation

Simple form	V-ing form
I could curb you could curb he could curb we could curb you could curb they could curb	I could be curbing you could be curbing he could be curbing we could be curbing you could be curbing they could be curbing
Perfect	V-ing perfect
I could have curbed you could have curbed he could have curbed we could have curbed you could have curbed they could have curbed	I could have been curbing you could have been curbing he could have been curbing we could have been curbing you could have been curbing they could have been curbing

Negation

Simple form	V-ing form
I couldn't curb you couldn't curb he couldn't curb we couldn't curb you couldn't curb they couldn't curb	I couldn't be curbing you couldn't be curbing he couldn't be curbing we couldn't be curbing you couldn't be curbing they couldn't be curbing
Perfect	V-ing perfect
I couldn't have curbed you couldn't have curbed he couldn't have curbed we couldn't have curbed you couldn't have curbed they couldn't have curbed	I couldn't have been curbing you couldn't have been curbing he couldn't have been curbing we couldn't have been curbing you couldn't have been curbing they couldn't have been curbing

Interrogative form

Simple form	V-ing form
could I curb? could you curb? could he curb? could we curb? could you curb? could they curb?	could I be curbing? could you be curbing? could he be curbing? could we be curbing? could you be curbing? could they be curbing?
Perfect	V-ing perfect
could I have curbed? could you have curbed? could he have curbed? could we have curbed? could you have curbed? could they have curbed?	could I have been curbing? could you have been curbing? could he have been curbing? could we have been curbing? could you have been curbing? could they have been curbing?

Interro-negative form

Simple form	V-ing form
couldn't I curb? couldn't you curb? couldn't he curb? couldn't we curb? couldn't you curb? couldn't they curb?	couldn't I be curbing? couldn't you be curbing? couldn't he be curbing? couldn't we be curbing? couldn't you be curbing? couldn't they be curbing?
Perfect	V-ing perfect
couldn't I have curbed? couldn't you have curbed? couldn't he have curbed? couldn't we have curbed? couldn't you have curbed? couldn't they have curbed?	couldn't I have been curbing? couldn't you have been curbing? couldn't he have been curbing? couldn't we have been curbing? couldn't you have been curbing? couldn't they have been curbing?