English verb conjugation
MUST BACKGROUND

Regular verb: background - backgrounded - backgrounded

Affirmation

Simple form	V-ing form
I must background you must background she must background we must background you must background they must background	I must be backgrounding you must be backgrounding she must be backgrounding we must be backgrounding you must be backgrounding they must be backgrounding
Perfect	V-ing perfect
I must have backgrounded you must have backgrounded she must have backgrounded we must have backgrounded you must have backgrounded they must have backgrounded	I must have been backgrounding you must have been backgrounding she must have been backgrounding we must have been backgrounding you must have been backgrounding they must have been backgrounding

Negation

Simple form	V-ing form
I mustn't background you mustn't background she mustn't background we mustn't background you mustn't background they mustn't background	I mustn't be backgrounding you mustn't be backgrounding she mustn't be backgrounding we mustn't be backgrounding you mustn't be backgrounding they mustn't be backgrounding
Perfect	V-ing perfect
I mustn't have backgrounded you mustn't have backgrounded she mustn't have backgrounded we mustn't have backgrounded you mustn't have backgrounded they mustn't have backgrounded	I mustn't have been backgrounding you mustn't have been backgrounding she mustn't have been backgrounding we mustn't have been backgrounding you mustn't have been backgrounding they mustn't have been backgrounding

Interrogative form

Simple form	V-ing form
must I background? must you background? must she background? must we background? must you background? must they background?	must I be backgrounding? must you be backgrounding? must she be backgrounding? must we be backgrounding? must you be backgrounding? must they be backgrounding?
Perfect	V-ing perfect
must I have backgrounded? must you have backgrounded? must she have backgrounded? must we have backgrounded? must you have backgrounded? must they have backgrounded?	must I have been backgrounding? must you have been backgrounding? must she have been backgrounding? must we have been backgrounding? must you have been backgrounding? must they have been backgrounding?

Interro-negative form

Simple form	V-ing form
mustn't I background? mustn't you background? mustn't she background? mustn't we background? mustn't you background? mustn't they background?	mustn't I be backgrounding? mustn't you be backgrounding? mustn't she be backgrounding? mustn't we be backgrounding? mustn't you be backgrounding? mustn't they be backgrounding?
Perfect	V-ing perfect
mustn't I have backgrounded? mustn't you have backgrounded? mustn't she have backgrounded? mustn't we have backgrounded? mustn't you have backgrounded? mustn't they have backgrounded?	mustn't I have been backgrounding? mustn't you have been backgrounding? mustn't she have been backgrounding? mustn't we have been backgrounding? mustn't you have been backgrounding? mustn't they have been backgrounding?