must burp
Regular verb: burp - burped- burped

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must burp
you must burp
he must burp
we must burp
you must burp
they must burp 	I must be burping
you must be burping
he must be burping
we must be burping
you must be burping
they must be burping	I must have burped
you must have burped
he must have burped
we must have burped
you must have burped
they must have burped	I must have been burping
you must have been burping
he must have been burping
we must have been burping
you must have been burping
they must have been burping	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not burp
you must not burp
he must not burp
we must not burp
you must not burp
they must not burp 	I must not be burping
you must not be burping
he must not be burping
we must not be burping
you must not be burping
they must not be burping	I must not have burped
you must not have burped
he must not have burped
we must not have burped
you must not have burped
they must not have burped	I must not have been burping
you must not have been burping
he must not have been burping
we must not have been burping
you must not have been burping
they must not have been burping	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I burp?
must you burp?
must he burp?
must we burp?
must you burp?
must they burp? 	must I be burping?
must you be burping?
must he be burping?
must we be burping?
must you be burping?
must they be burping? 	must I have burped?
must you have burped?
must he have burped?
must we have burped?
must you have burped?
must they have burped? 	must I have been burping?
must you have been burping?
must he have been burping?
must we have been burping?
must you have been burping?
must they have been burping? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not burp?
must you not burp?
must he not burp?
must we not burp?
must you not burp?
must they not burp? 	must I not be burping?
must you not be burping?
must he not be burping?
must we not be burping?
must you not be burping?
must they not be burping? 	must I not have burped?
must you not have burped?
must he not have burped?
must we not have burped?
must you not have burped?
must they not have burped? 	must I not have been burping?
must you not have been burping?
must he not have been burping?
must we not have been burping?
must you not have been burping?
must they not have been burping?