English verb conjugation
MUST CHUFF

Regular verb: chuff - chuffed - chuffed

Affirmation

Simple form	V-ing form
I must chuff you must chuff he must chuff we must chuff you must chuff they must chuff	I must be chuffing you must be chuffing he must be chuffing we must be chuffing you must be chuffing they must be chuffing
Perfect	V-ing perfect
I must have chuffed you must have chuffed he must have chuffed we must have chuffed you must have chuffed they must have chuffed	I must have been chuffing you must have been chuffing he must have been chuffing we must have been chuffing you must have been chuffing they must have been chuffing

Negation

Simple form	V-ing form
I must not chuff you must not chuff he must not chuff we must not chuff you must not chuff they must not chuff	I must not be chuffing you must not be chuffing he must not be chuffing we must not be chuffing you must not be chuffing they must not be chuffing
Perfect	V-ing perfect
I must not have chuffed you must not have chuffed he must not have chuffed we must not have chuffed you must not have chuffed they must not have chuffed	I must not have been chuffing you must not have been chuffing he must not have been chuffing we must not have been chuffing you must not have been chuffing they must not have been chuffing

Interrogative form

Simple form	V-ing form
must I chuff? must you chuff? must he chuff? must we chuff? must you chuff? must they chuff?	must I be chuffing? must you be chuffing? must he be chuffing? must we be chuffing? must you be chuffing? must they be chuffing?
Perfect	V-ing perfect
must I have chuffed? must you have chuffed? must he have chuffed? must we have chuffed? must you have chuffed? must they have chuffed?	must I have been chuffing? must you have been chuffing? must he have been chuffing? must we have been chuffing? must you have been chuffing? must they have been chuffing?

Interro-negative form

Simple form	V-ing form
must I not chuff? must you not chuff? must he not chuff? must we not chuff? must you not chuff? must they not chuff?	must I not be chuffing? must you not be chuffing? must he not be chuffing? must we not be chuffing? must you not be chuffing? must they not be chuffing?
Perfect	V-ing perfect
must I not have chuffed? must you not have chuffed? must he not have chuffed? must we not have chuffed? must you not have chuffed? must they not have chuffed?	must I not have been chuffing? must you not have been chuffing? must he not have been chuffing? must we not have been chuffing? must you not have been chuffing? must they not have been chuffing?