I must underlie you must underlie he must underlie we must underlie you must underlie they must underlie
V-ing form
I must be underlying you must be underlying he must be underlying we must be underlying you must be underlying they must be underlying
Perfect
I must have underlain you must have underlain he must have underlain we must have underlain you must have underlain they must have underlain
V-ing perfect
I must have been underlying you must have been underlying he must have been underlying we must have been underlying you must have been underlying they must have been underlying
Negation
Simple form
I must not underlie you must not underlie he must not underlie we must not underlie you must not underlie they must not underlie
V-ing form
I must not be underlying you must not be underlying he must not be underlying we must not be underlying you must not be underlying they must not be underlying
Perfect
I must not have underlain you must not have underlain he must not have underlain we must not have underlain you must not have underlain they must not have underlain
V-ing perfect
I must not have been underlying you must not have been underlying he must not have been underlying we must not have been underlying you must not have been underlying they must not have been underlying
Interrogative form
Simple form
must I underlie? must you underlie? must he underlie? must we underlie? must you underlie? must they underlie?
V-ing form
must I be underlying? must you be underlying? must he be underlying? must we be underlying? must you be underlying? must they be underlying?
Perfect
must I have underlain? must you have underlain? must he have underlain? must we have underlain? must you have underlain? must they have underlain?
V-ing perfect
must I have been underlying? must you have been underlying? must he have been underlying? must we have been underlying? must you have been underlying? must they have been underlying?
Interro-negative form
Simple form
must I not underlie? must you not underlie? must he not underlie? must we not underlie? must you not underlie? must they not underlie?
V-ing form
must I not be underlying? must you not be underlying? must he not be underlying? must we not be underlying? must you not be underlying? must they not be underlying?
Perfect
must I not have underlain? must you not have underlain? must he not have underlain? must we not have underlain? must you not have underlain? must they not have underlain?
V-ing perfect
must I not have been underlying? must you not have been underlying? must he not have been underlying? must we not have been underlying? must you not have been underlying? must they not have been underlying?