English verb conjugation
CAN CURTAIN

Regular verb: curtain - curtained - curtained

Affirmation

Simple form	V-ing form
I can curtain you can curtain he can curtain we can curtain you can curtain they can curtain	I can be curtaining you can be curtaining he can be curtaining we can be curtaining you can be curtaining they can be curtaining
Perfect	V-ing perfect
I can have curtained you can have curtained he can have curtained we can have curtained you can have curtained they can have curtained	I can have been curtaining you can have been curtaining he can have been curtaining we can have been curtaining you can have been curtaining they can have been curtaining

Negation

Simple form	V-ing form
I cannot curtain you cannot curtain he cannot curtain we cannot curtain you cannot curtain they cannot curtain	I cannot be curtaining you cannot be curtaining he cannot be curtaining we cannot be curtaining you cannot be curtaining they cannot be curtaining
Perfect	V-ing perfect
I cannot have curtained you cannot have curtained he cannot have curtained we cannot have curtained you cannot have curtained they cannot have curtained	I cannot have been curtaining you cannot have been curtaining he cannot have been curtaining we cannot have been curtaining you cannot have been curtaining they cannot have been curtaining

Interrogative form

Simple form	V-ing form
can I curtain? can you curtain? can he curtain? can we curtain? can you curtain? can they curtain?	can I be curtaining? can you be curtaining? can he be curtaining? can we be curtaining? can you be curtaining? can they be curtaining?
Perfect	V-ing perfect
can I have curtained? can you have curtained? can he have curtained? can we have curtained? can you have curtained? can they have curtained?	can I have been curtaining? can you have been curtaining? can he have been curtaining? can we have been curtaining? can you have been curtaining? can they have been curtaining?

Interro-negative form

Simple form	V-ing form
can I not curtain? can you not curtain? can he not curtain? can we not curtain? can you not curtain? can they not curtain?	can I not be curtaining? can you not be curtaining? can he not be curtaining? can we not be curtaining? can you not be curtaining? can they not be curtaining?
Perfect	V-ing perfect
can I not have curtained? can you not have curtained? can he not have curtained? can we not have curtained? can you not have curtained? can they not have curtained?	can I not have been curtaining? can you not have been curtaining? can he not have been curtaining? can we not have been curtaining? can you not have been curtaining? can they not have been curtaining?