English verb conjugation
MUST UNDERSTAND

Irregular verb: understand - understood - understood

Affirmation

Simple form	V-ing form
I must understand you must understand she must understand we must understand you must understand they must understand	I must be understanding you must be understanding she must be understanding we must be understanding you must be understanding they must be understanding
Perfect	V-ing perfect
I must have understood you must have understood she must have understood we must have understood you must have understood they must have understood	I must have been understanding you must have been understanding she must have been understanding we must have been understanding you must have been understanding they must have been understanding

Negation

Simple form	V-ing form
I must not understand you must not understand she must not understand we must not understand you must not understand they must not understand	I must not be understanding you must not be understanding she must not be understanding we must not be understanding you must not be understanding they must not be understanding
Perfect	V-ing perfect
I must not have understood you must not have understood she must not have understood we must not have understood you must not have understood they must not have understood	I must not have been understanding you must not have been understanding she must not have been understanding we must not have been understanding you must not have been understanding they must not have been understanding

Interrogative form

Simple form	V-ing form
must I understand? must you understand? must she understand? must we understand? must you understand? must they understand?	must I be understanding? must you be understanding? must she be understanding? must we be understanding? must you be understanding? must they be understanding?
Perfect	V-ing perfect
must I have understood? must you have understood? must she have understood? must we have understood? must you have understood? must they have understood?	must I have been understanding? must you have been understanding? must she have been understanding? must we have been understanding? must you have been understanding? must they have been understanding?

Interro-negative form

Simple form	V-ing form
must I not understand? must you not understand? must she not understand? must we not understand? must you not understand? must they not understand?	must I not be understanding? must you not be understanding? must she not be understanding? must we not be understanding? must you not be understanding? must they not be understanding?
Perfect	V-ing perfect
must I not have understood? must you not have understood? must she not have understood? must we not have understood? must you not have understood? must they not have understood?	must I not have been understanding? must you not have been understanding? must she not have been understanding? must we not have been understanding? must you not have been understanding? must they not have been understanding?