English verb conjugation
MUST UNDERTAIN

Regular verb: undertain - undertained - undertained

Affirmation

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

Negation

Simple form	V-ing form
I must not undertain you must not undertain she must not undertain we must not undertain you must not undertain they must not undertain	I must not be undertaining you must not be undertaining she must not be undertaining we must not be undertaining you must not be undertaining they must not be undertaining
Perfect	V-ing perfect
I must not have undertained you must not have undertained she must not have undertained we must not have undertained you must not have undertained they must not have undertained	I must not have been undertaining you must not have been undertaining she must not have been undertaining we must not have been undertaining you must not have been undertaining they must not have been undertaining

Interrogative form

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

Interro-negative form

Simple form	V-ing form
must I not undertain? must you not undertain? must she not undertain? must we not undertain? must you not undertain? must they not undertain?	must I not be undertaining? must you not be undertaining? must she not be undertaining? must we not be undertaining? must you not be undertaining? must they not be undertaining?
Perfect	V-ing perfect
must I not have undertained? must you not have undertained? must she not have undertained? must we not have undertained? must you not have undertained? must they not have undertained?	must I not have been undertaining? must you not have been undertaining? must she not have been undertaining? must we not have been undertaining? must you not have been undertaining? must they not have been undertaining?