English verb conjugation
MUST UNDERTAKE

Irregular verb: undertake - undertook - undertaken

Affirmation

Simple form	V-ing form
I must undertake you must undertake she must undertake we must undertake you must undertake they must undertake	I must be undertaking you must be undertaking she must be undertaking we must be undertaking you must be undertaking they must be undertaking
Perfect	V-ing perfect
I must have undertaken you must have undertaken she must have undertaken we must have undertaken you must have undertaken they must have undertaken	I must have been undertaking you must have been undertaking she must have been undertaking we must have been undertaking you must have been undertaking they must have been undertaking

Negation

Simple form	V-ing form
I mustn't undertake you mustn't undertake she mustn't undertake we mustn't undertake you mustn't undertake they mustn't undertake	I mustn't be undertaking you mustn't be undertaking she mustn't be undertaking we mustn't be undertaking you mustn't be undertaking they mustn't be undertaking
Perfect	V-ing perfect
I mustn't have undertaken you mustn't have undertaken she mustn't have undertaken we mustn't have undertaken you mustn't have undertaken they mustn't have undertaken	I mustn't have been undertaking you mustn't have been undertaking she mustn't have been undertaking we mustn't have been undertaking you mustn't have been undertaking they mustn't have been undertaking

Interrogative form

Simple form	V-ing form
must I undertake? must you undertake? must she undertake? must we undertake? must you undertake? must they undertake?	must I be undertaking? must you be undertaking? must she be undertaking? must we be undertaking? must you be undertaking? must they be undertaking?
Perfect	V-ing perfect
must I have undertaken? must you have undertaken? must she have undertaken? must we have undertaken? must you have undertaken? must they have undertaken?	must I have been undertaking? must you have been undertaking? must she have been undertaking? must we have been undertaking? must you have been undertaking? must they have been undertaking?

Interro-negative form

Simple form	V-ing form
mustn't I undertake? mustn't you undertake? mustn't she undertake? mustn't we undertake? mustn't you undertake? mustn't they undertake?	mustn't I be undertaking? mustn't you be undertaking? mustn't she be undertaking? mustn't we be undertaking? mustn't you be undertaking? mustn't they be undertaking?
Perfect	V-ing perfect
mustn't I have undertaken? mustn't you have undertaken? mustn't she have undertaken? mustn't we have undertaken? mustn't you have undertaken? mustn't they have undertaken?	mustn't I have been undertaking? mustn't you have been undertaking? mustn't she have been undertaking? mustn't we have been undertaking? mustn't you have been undertaking? mustn't they have been undertaking?