English verb conjugation
CAN UNDERTAIN

Regular verb: undertain - undertained - undertained

Affirmation

Simple form	V-ing form
I can undertain you can undertain he can undertain we can undertain you can undertain they can undertain	I can be undertaining you can be undertaining he can be undertaining we can be undertaining you can be undertaining they can be undertaining
Perfect	V-ing perfect
I can have undertained you can have undertained he can have undertained we can have undertained you can have undertained they can have undertained	I can have been undertaining you can have been undertaining he can have been undertaining we can have been undertaining you can have been undertaining they can have been undertaining

Negation

Simple form	V-ing form
I can't undertain you can't undertain he can't undertain we can't undertain you can't undertain they can't undertain	I can't be undertaining you can't be undertaining he can't be undertaining we can't be undertaining you can't be undertaining they can't be undertaining
Perfect	V-ing perfect
I can't have undertained you can't have undertained he can't have undertained we can't have undertained you can't have undertained they can't have undertained	I can't have been undertaining you can't have been undertaining he can't have been undertaining we can't have been undertaining you can't have been undertaining they can't have been undertaining

Interrogative form

Simple form	V-ing form
can I undertain? can you undertain? can he undertain? can we undertain? can you undertain? can they undertain?	can I be undertaining? can you be undertaining? can he be undertaining? can we be undertaining? can you be undertaining? can they be undertaining?
Perfect	V-ing perfect
can I have undertained? can you have undertained? can he have undertained? can we have undertained? can you have undertained? can they have undertained?	can I have been undertaining? can you have been undertaining? can he have been undertaining? can we have been undertaining? can you have been undertaining? can they have been undertaining?

Interro-negative form

Simple form	V-ing form
can't I undertain? can't you undertain? can't he undertain? can't we undertain? can't you undertain? can't they undertain?	can't I be undertaining? can't you be undertaining? can't he be undertaining? can't we be undertaining? can't you be undertaining? can't they be undertaining?
Perfect	V-ing perfect
can't I have undertained? can't you have undertained? can't he have undertained? can't we have undertained? can't you have undertained? can't they have undertained?	can't I have been undertaining? can't you have been undertaining? can't he have been undertaining? can't we have been undertaining? can't you have been undertaining? can't they have been undertaining?