English verb conjugation
MUST PIFFLE

Regular verb: piffle - piffled - piffled

Affirmation

Simple form	V-ing form
I must piffle you must piffle he must piffle we must piffle you must piffle they must piffle	I must be piffling you must be piffling he must be piffling we must be piffling you must be piffling they must be piffling
Perfect	V-ing perfect
I must have piffled you must have piffled he must have piffled we must have piffled you must have piffled they must have piffled	I must have been piffling you must have been piffling he must have been piffling we must have been piffling you must have been piffling they must have been piffling

Negation

Simple form	V-ing form
I mustn't piffle you mustn't piffle he mustn't piffle we mustn't piffle you mustn't piffle they mustn't piffle	I mustn't be piffling you mustn't be piffling he mustn't be piffling we mustn't be piffling you mustn't be piffling they mustn't be piffling
Perfect	V-ing perfect
I mustn't have piffled you mustn't have piffled he mustn't have piffled we mustn't have piffled you mustn't have piffled they mustn't have piffled	I mustn't have been piffling you mustn't have been piffling he mustn't have been piffling we mustn't have been piffling you mustn't have been piffling they mustn't have been piffling

Interrogative form

Simple form	V-ing form
must I piffle? must you piffle? must he piffle? must we piffle? must you piffle? must they piffle?	must I be piffling? must you be piffling? must he be piffling? must we be piffling? must you be piffling? must they be piffling?
Perfect	V-ing perfect
must I have piffled? must you have piffled? must he have piffled? must we have piffled? must you have piffled? must they have piffled?	must I have been piffling? must you have been piffling? must he have been piffling? must we have been piffling? must you have been piffling? must they have been piffling?

Interro-negative form

Simple form	V-ing form
mustn't I piffle? mustn't you piffle? mustn't he piffle? mustn't we piffle? mustn't you piffle? mustn't they piffle?	mustn't I be piffling? mustn't you be piffling? mustn't he be piffling? mustn't we be piffling? mustn't you be piffling? mustn't they be piffling?
Perfect	V-ing perfect
mustn't I have piffled? mustn't you have piffled? mustn't he have piffled? mustn't we have piffled? mustn't you have piffled? mustn't they have piffled?	mustn't I have been piffling? mustn't you have been piffling? mustn't he have been piffling? mustn't we have been piffling? mustn't you have been piffling? mustn't they have been piffling?