must puff
Regular verb: puff - puffed- puffed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must puff
you must puff
she must puff
we must puff
you must puff
they must puff 	I must be puffing
you must be puffing
she must be puffing
we must be puffing
you must be puffing
they must be puffing	I must have puffed
you must have puffed
she must have puffed
we must have puffed
you must have puffed
they must have puffed	I must have been puffing
you must have been puffing
she must have been puffing
we must have been puffing
you must have been puffing
they must have been puffing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not puff
you must not puff
she must not puff
we must not puff
you must not puff
they must not puff 	I must not be puffing
you must not be puffing
she must not be puffing
we must not be puffing
you must not be puffing
they must not be puffing	I must not have puffed
you must not have puffed
she must not have puffed
we must not have puffed
you must not have puffed
they must not have puffed	I must not have been puffing
you must not have been puffing
she must not have been puffing
we must not have been puffing
you must not have been puffing
they must not have been puffing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I puff?
must you puff?
must she puff?
must we puff?
must you puff?
must they puff? 	must I be puffing?
must you be puffing?
must she be puffing?
must we be puffing?
must you be puffing?
must they be puffing? 	must I have puffed?
must you have puffed?
must she have puffed?
must we have puffed?
must you have puffed?
must they have puffed? 	must I have been puffing?
must you have been puffing?
must she have been puffing?
must we have been puffing?
must you have been puffing?
must they have been puffing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not puff?
must you not puff?
must she not puff?
must we not puff?
must you not puff?
must they not puff? 	must I not be puffing?
must you not be puffing?
must she not be puffing?
must we not be puffing?
must you not be puffing?
must they not be puffing? 	must I not have puffed?
must you not have puffed?
must she not have puffed?
must we not have puffed?
must you not have puffed?
must they not have puffed? 	must I not have been puffing?
must you not have been puffing?
must she not have been puffing?
must we not have been puffing?
must you not have been puffing?
must they not have been puffing?