English verb conjugation
MUST RIFFLE

Regular verb: riffle - riffled - riffled

Affirmation

Simple form	V-ing form
I must riffle you must riffle he must riffle we must riffle you must riffle they must riffle	I must be riffling you must be riffling he must be riffling we must be riffling you must be riffling they must be riffling
Perfect	V-ing perfect
I must have riffled you must have riffled he must have riffled we must have riffled you must have riffled they must have riffled	I must have been riffling you must have been riffling he must have been riffling we must have been riffling you must have been riffling they must have been riffling

Negation

Simple form	V-ing form
I mustn't riffle you mustn't riffle he mustn't riffle we mustn't riffle you mustn't riffle they mustn't riffle	I mustn't be riffling you mustn't be riffling he mustn't be riffling we mustn't be riffling you mustn't be riffling they mustn't be riffling
Perfect	V-ing perfect
I mustn't have riffled you mustn't have riffled he mustn't have riffled we mustn't have riffled you mustn't have riffled they mustn't have riffled	I mustn't have been riffling you mustn't have been riffling he mustn't have been riffling we mustn't have been riffling you mustn't have been riffling they mustn't have been riffling

Interrogative form

Simple form	V-ing form
must I riffle? must you riffle? must he riffle? must we riffle? must you riffle? must they riffle?	must I be riffling? must you be riffling? must he be riffling? must we be riffling? must you be riffling? must they be riffling?
Perfect	V-ing perfect
must I have riffled? must you have riffled? must he have riffled? must we have riffled? must you have riffled? must they have riffled?	must I have been riffling? must you have been riffling? must he have been riffling? must we have been riffling? must you have been riffling? must they have been riffling?

Interro-negative form

Simple form	V-ing form
mustn't I riffle? mustn't you riffle? mustn't he riffle? mustn't we riffle? mustn't you riffle? mustn't they riffle?	mustn't I be riffling? mustn't you be riffling? mustn't he be riffling? mustn't we be riffling? mustn't you be riffling? mustn't they be riffling?
Perfect	V-ing perfect
mustn't I have riffled? mustn't you have riffled? mustn't he have riffled? mustn't we have riffled? mustn't you have riffled? mustn't they have riffled?	mustn't I have been riffling? mustn't you have been riffling? mustn't he have been riffling? mustn't we have been riffling? mustn't you have been riffling? mustn't they have been riffling?