English verb conjugation
MUST LUMBER

Regular verb: lumber - lumbered - lumbered

Affirmation

Simple form	V-ing form
I must lumber you must lumber she must lumber we must lumber you must lumber they must lumber	I must be lumbering you must be lumbering she must be lumbering we must be lumbering you must be lumbering they must be lumbering
Perfect	V-ing perfect
I must have lumbered you must have lumbered she must have lumbered we must have lumbered you must have lumbered they must have lumbered	I must have been lumbering you must have been lumbering she must have been lumbering we must have been lumbering you must have been lumbering they must have been lumbering

Negation

Simple form	V-ing form
I must not lumber you must not lumber she must not lumber we must not lumber you must not lumber they must not lumber	I must not be lumbering you must not be lumbering she must not be lumbering we must not be lumbering you must not be lumbering they must not be lumbering
Perfect	V-ing perfect
I must not have lumbered you must not have lumbered she must not have lumbered we must not have lumbered you must not have lumbered they must not have lumbered	I must not have been lumbering you must not have been lumbering she must not have been lumbering we must not have been lumbering you must not have been lumbering they must not have been lumbering

Interrogative form

Simple form	V-ing form
must I lumber? must you lumber? must she lumber? must we lumber? must you lumber? must they lumber?	must I be lumbering? must you be lumbering? must she be lumbering? must we be lumbering? must you be lumbering? must they be lumbering?
Perfect	V-ing perfect
must I have lumbered? must you have lumbered? must she have lumbered? must we have lumbered? must you have lumbered? must they have lumbered?	must I have been lumbering? must you have been lumbering? must she have been lumbering? must we have been lumbering? must you have been lumbering? must they have been lumbering?

Interro-negative form

Simple form	V-ing form
must I not lumber? must you not lumber? must she not lumber? must we not lumber? must you not lumber? must they not lumber?	must I not be lumbering? must you not be lumbering? must she not be lumbering? must we not be lumbering? must you not be lumbering? must they not be lumbering?
Perfect	V-ing perfect
must I not have lumbered? must you not have lumbered? must she not have lumbered? must we not have lumbered? must you not have lumbered? must they not have lumbered?	must I not have been lumbering? must you not have been lumbering? must she not have been lumbering? must we not have been lumbering? must you not have been lumbering? must they not have been lumbering?