English verb conjugation
MUST YAP

Regular verb: yap - yapped - yapped

Affirmation

Simple form	V-ing form
I must yap you must yap he must yap we must yap you must yap they must yap	I must be yapping you must be yapping he must be yapping we must be yapping you must be yapping they must be yapping
Perfect	V-ing perfect
I must have yapped you must have yapped he must have yapped we must have yapped you must have yapped they must have yapped	I must have been yapping you must have been yapping he must have been yapping we must have been yapping you must have been yapping they must have been yapping

Negation

Simple form	V-ing form
I mustn't yap you mustn't yap he mustn't yap we mustn't yap you mustn't yap they mustn't yap	I mustn't be yapping you mustn't be yapping he mustn't be yapping we mustn't be yapping you mustn't be yapping they mustn't be yapping
Perfect	V-ing perfect
I mustn't have yapped you mustn't have yapped he mustn't have yapped we mustn't have yapped you mustn't have yapped they mustn't have yapped	I mustn't have been yapping you mustn't have been yapping he mustn't have been yapping we mustn't have been yapping you mustn't have been yapping they mustn't have been yapping

Interrogative form

Simple form	V-ing form
must I yap? must you yap? must he yap? must we yap? must you yap? must they yap?	must I be yapping? must you be yapping? must he be yapping? must we be yapping? must you be yapping? must they be yapping?
Perfect	V-ing perfect
must I have yapped? must you have yapped? must he have yapped? must we have yapped? must you have yapped? must they have yapped?	must I have been yapping? must you have been yapping? must he have been yapping? must we have been yapping? must you have been yapping? must they have been yapping?

Interro-negative form

Simple form	V-ing form
mustn't I yap? mustn't you yap? mustn't he yap? mustn't we yap? mustn't you yap? mustn't they yap?	mustn't I be yapping? mustn't you be yapping? mustn't he be yapping? mustn't we be yapping? mustn't you be yapping? mustn't they be yapping?
Perfect	V-ing perfect
mustn't I have yapped? mustn't you have yapped? mustn't he have yapped? mustn't we have yapped? mustn't you have yapped? mustn't they have yapped?	mustn't I have been yapping? mustn't you have been yapping? mustn't he have been yapping? mustn't we have been yapping? mustn't you have been yapping? mustn't they have been yapping?