English verb conjugation
MUST UNDERLIE

Irregular verb: underlie - underlay - underlain

Affirmation

Simple form	V-ing form
I must underlie you must underlie she must underlie we must underlie you must underlie they must underlie	I must be underlying you must be underlying she must be underlying we must be underlying you must be underlying they must be underlying
Perfect	V-ing perfect
I must have underlain you must have underlain she must have underlain we must have underlain you must have underlain they must have underlain	I must have been underlying you must have been underlying she must have been underlying we must have been underlying you must have been underlying they must have been underlying

Negation

Simple form	V-ing form
I mustn't underlie you mustn't underlie she mustn't underlie we mustn't underlie you mustn't underlie they mustn't underlie	I mustn't be underlying you mustn't be underlying she mustn't be underlying we mustn't be underlying you mustn't be underlying they mustn't be underlying
Perfect	V-ing perfect
I mustn't have underlain you mustn't have underlain she mustn't have underlain we mustn't have underlain you mustn't have underlain they mustn't have underlain	I mustn't have been underlying you mustn't have been underlying she mustn't have been underlying we mustn't have been underlying you mustn't have been underlying they mustn't have been underlying

Interrogative form

Simple form	V-ing form
must I underlie? must you underlie? must she underlie? must we underlie? must you underlie? must they underlie?	must I be underlying? must you be underlying? must she be underlying? must we be underlying? must you be underlying? must they be underlying?
Perfect	V-ing perfect
must I have underlain? must you have underlain? must she have underlain? must we have underlain? must you have underlain? must they have underlain?	must I have been underlying? must you have been underlying? must she have been underlying? must we have been underlying? must you have been underlying? must they have been underlying?

Interro-negative form

Simple form	V-ing form
mustn't I underlie? mustn't you underlie? mustn't she underlie? mustn't we underlie? mustn't you underlie? mustn't they underlie?	mustn't I be underlying? mustn't you be underlying? mustn't she be underlying? mustn't we be underlying? mustn't you be underlying? mustn't they be underlying?
Perfect	V-ing perfect
mustn't I have underlain? mustn't you have underlain? mustn't she have underlain? mustn't we have underlain? mustn't you have underlain? mustn't they have underlain?	mustn't I have been underlying? mustn't you have been underlying? mustn't she have been underlying? mustn't we have been underlying? mustn't you have been underlying? mustn't they have been underlying?