English verb conjugation
MUST UNDERSIGN

Regular verb: undersign - undersigned - undersigned

Affirmation

Simple form	V-ing form
I must undersign you must undersign he must undersign we must undersign you must undersign they must undersign	I must be undersigning you must be undersigning he must be undersigning we must be undersigning you must be undersigning they must be undersigning
Perfect	V-ing perfect
I must have undersigned you must have undersigned he must have undersigned we must have undersigned you must have undersigned they must have undersigned	I must have been undersigning you must have been undersigning he must have been undersigning we must have been undersigning you must have been undersigning they must have been undersigning

Negation

Simple form	V-ing form
I must not undersign you must not undersign he must not undersign we must not undersign you must not undersign they must not undersign	I must not be undersigning you must not be undersigning he must not be undersigning we must not be undersigning you must not be undersigning they must not be undersigning
Perfect	V-ing perfect
I must not have undersigned you must not have undersigned he must not have undersigned we must not have undersigned you must not have undersigned they must not have undersigned	I must not have been undersigning you must not have been undersigning he must not have been undersigning we must not have been undersigning you must not have been undersigning they must not have been undersigning

Interrogative form

Simple form	V-ing form
must I undersign? must you undersign? must he undersign? must we undersign? must you undersign? must they undersign?	must I be undersigning? must you be undersigning? must he be undersigning? must we be undersigning? must you be undersigning? must they be undersigning?
Perfect	V-ing perfect
must I have undersigned? must you have undersigned? must he have undersigned? must we have undersigned? must you have undersigned? must they have undersigned?	must I have been undersigning? must you have been undersigning? must he have been undersigning? must we have been undersigning? must you have been undersigning? must they have been undersigning?

Interro-negative form

Simple form	V-ing form
must I not undersign? must you not undersign? must he not undersign? must we not undersign? must you not undersign? must they not undersign?	must I not be undersigning? must you not be undersigning? must he not be undersigning? must we not be undersigning? must you not be undersigning? must they not be undersigning?
Perfect	V-ing perfect
must I not have undersigned? must you not have undersigned? must he not have undersigned? must we not have undersigned? must you not have undersigned? must they not have undersigned?	must I not have been undersigning? must you not have been undersigning? must he not have been undersigning? must we not have been undersigning? must you not have been undersigning? must they not have been undersigning?