must flap
Regular verb: flap - flapped- flapped

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must flap
you must flap
she must flap
we must flap
you must flap
they must flap 	I must be flapping
you must be flapping
she must be flapping
we must be flapping
you must be flapping
they must be flapping	I must have flapped
you must have flapped
she must have flapped
we must have flapped
you must have flapped
they must have flapped	I must have been flapping
you must have been flapping
she must have been flapping
we must have been flapping
you must have been flapping
they must have been flapping	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not flap
you must not flap
she must not flap
we must not flap
you must not flap
they must not flap 	I must not be flapping
you must not be flapping
she must not be flapping
we must not be flapping
you must not be flapping
they must not be flapping	I must not have flapped
you must not have flapped
she must not have flapped
we must not have flapped
you must not have flapped
they must not have flapped	I must not have been flapping
you must not have been flapping
she must not have been flapping
we must not have been flapping
you must not have been flapping
they must not have been flapping	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I flap?
must you flap?
must she flap?
must we flap?
must you flap?
must they flap? 	must I be flapping?
must you be flapping?
must she be flapping?
must we be flapping?
must you be flapping?
must they be flapping? 	must I have flapped?
must you have flapped?
must she have flapped?
must we have flapped?
must you have flapped?
must they have flapped? 	must I have been flapping?
must you have been flapping?
must she have been flapping?
must we have been flapping?
must you have been flapping?
must they have been flapping? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not flap?
must you not flap?
must she not flap?
must we not flap?
must you not flap?
must they not flap? 	must I not be flapping?
must you not be flapping?
must she not be flapping?
must we not be flapping?
must you not be flapping?
must they not be flapping? 	must I not have flapped?
must you not have flapped?
must she not have flapped?
must we not have flapped?
must you not have flapped?
must they not have flapped? 	must I not have been flapping?
must you not have been flapping?
must she not have been flapping?
must we not have been flapping?
must you not have been flapping?
must they not have been flapping?