English verb conjugation
MUST PLUMB

Regular verb: plumb - plumbed - plumbed

Affirmation

Simple form	V-ing form
I must plumb you must plumb he must plumb we must plumb you must plumb they must plumb	I must be plumbing you must be plumbing he must be plumbing we must be plumbing you must be plumbing they must be plumbing
Perfect	V-ing perfect
I must have plumbed you must have plumbed he must have plumbed we must have plumbed you must have plumbed they must have plumbed	I must have been plumbing you must have been plumbing he must have been plumbing we must have been plumbing you must have been plumbing they must have been plumbing

Negation

Simple form	V-ing form
I mustn't plumb you mustn't plumb he mustn't plumb we mustn't plumb you mustn't plumb they mustn't plumb	I mustn't be plumbing you mustn't be plumbing he mustn't be plumbing we mustn't be plumbing you mustn't be plumbing they mustn't be plumbing
Perfect	V-ing perfect
I mustn't have plumbed you mustn't have plumbed he mustn't have plumbed we mustn't have plumbed you mustn't have plumbed they mustn't have plumbed	I mustn't have been plumbing you mustn't have been plumbing he mustn't have been plumbing we mustn't have been plumbing you mustn't have been plumbing they mustn't have been plumbing

Interrogative form

Simple form	V-ing form
must I plumb? must you plumb? must he plumb? must we plumb? must you plumb? must they plumb?	must I be plumbing? must you be plumbing? must he be plumbing? must we be plumbing? must you be plumbing? must they be plumbing?
Perfect	V-ing perfect
must I have plumbed? must you have plumbed? must he have plumbed? must we have plumbed? must you have plumbed? must they have plumbed?	must I have been plumbing? must you have been plumbing? must he have been plumbing? must we have been plumbing? must you have been plumbing? must they have been plumbing?

Interro-negative form

Simple form	V-ing form
mustn't I plumb? mustn't you plumb? mustn't he plumb? mustn't we plumb? mustn't you plumb? mustn't they plumb?	mustn't I be plumbing? mustn't you be plumbing? mustn't he be plumbing? mustn't we be plumbing? mustn't you be plumbing? mustn't they be plumbing?
Perfect	V-ing perfect
mustn't I have plumbed? mustn't you have plumbed? mustn't he have plumbed? mustn't we have plumbed? mustn't you have plumbed? mustn't they have plumbed?	mustn't I have been plumbing? mustn't you have been plumbing? mustn't he have been plumbing? mustn't we have been plumbing? mustn't you have been plumbing? mustn't they have been plumbing?