English verb conjugation
MUST BURP

Regular verb: burp - burped - burped

Affirmation

Simple form	V-ing form
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
Perfect	V-ing perfect
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
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
Perfect	V-ing perfect
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
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?
Perfect	V-ing perfect
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
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?
Perfect	V-ing perfect
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?