English verb conjugation
MUST STIFLE

Regular verb: stifle - stifled - stifled

Affirmation

Simple form	V-ing form
I must stifle you must stifle he must stifle we must stifle you must stifle they must stifle	I must be stifling you must be stifling he must be stifling we must be stifling you must be stifling they must be stifling
Perfect	V-ing perfect
I must have stifled you must have stifled he must have stifled we must have stifled you must have stifled they must have stifled	I must have been stifling you must have been stifling he must have been stifling we must have been stifling you must have been stifling they must have been stifling

Negation

Simple form	V-ing form
I mustn't stifle you mustn't stifle he mustn't stifle we mustn't stifle you mustn't stifle they mustn't stifle	I mustn't be stifling you mustn't be stifling he mustn't be stifling we mustn't be stifling you mustn't be stifling they mustn't be stifling
Perfect	V-ing perfect
I mustn't have stifled you mustn't have stifled he mustn't have stifled we mustn't have stifled you mustn't have stifled they mustn't have stifled	I mustn't have been stifling you mustn't have been stifling he mustn't have been stifling we mustn't have been stifling you mustn't have been stifling they mustn't have been stifling

Interrogative form

Simple form	V-ing form
must I stifle? must you stifle? must he stifle? must we stifle? must you stifle? must they stifle?	must I be stifling? must you be stifling? must he be stifling? must we be stifling? must you be stifling? must they be stifling?
Perfect	V-ing perfect
must I have stifled? must you have stifled? must he have stifled? must we have stifled? must you have stifled? must they have stifled?	must I have been stifling? must you have been stifling? must he have been stifling? must we have been stifling? must you have been stifling? must they have been stifling?

Interro-negative form

Simple form	V-ing form
mustn't I stifle? mustn't you stifle? mustn't he stifle? mustn't we stifle? mustn't you stifle? mustn't they stifle?	mustn't I be stifling? mustn't you be stifling? mustn't he be stifling? mustn't we be stifling? mustn't you be stifling? mustn't they be stifling?
Perfect	V-ing perfect
mustn't I have stifled? mustn't you have stifled? mustn't he have stifled? mustn't we have stifled? mustn't you have stifled? mustn't they have stifled?	mustn't I have been stifling? mustn't you have been stifling? mustn't he have been stifling? mustn't we have been stifling? mustn't you have been stifling? mustn't they have been stifling?