must flock
Regular verb: flock - flocked- flocked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must flock
you must flock
she must flock
we must flock
you must flock
they must flock 	I must be flocking
you must be flocking
she must be flocking
we must be flocking
you must be flocking
they must be flocking	I must have flocked
you must have flocked
she must have flocked
we must have flocked
you must have flocked
they must have flocked	I must have been flocking
you must have been flocking
she must have been flocking
we must have been flocking
you must have been flocking
they must have been flocking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't flock
you mustn't flock
she mustn't flock
we mustn't flock
you mustn't flock
they mustn't flock 	I mustn't be flocking
you mustn't be flocking
she mustn't be flocking
we mustn't be flocking
you mustn't be flocking
they mustn't be flocking	I mustn't have flocked
you mustn't have flocked
she mustn't have flocked
we mustn't have flocked
you mustn't have flocked
they mustn't have flocked	I mustn't have been flocking
you mustn't have been flocking
she mustn't have been flocking
we mustn't have been flocking
you mustn't have been flocking
they mustn't have been flocking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I flock?
must you flock?
must she flock?
must we flock?
must you flock?
must they flock? 	must I be flocking?
must you be flocking?
must she be flocking?
must we be flocking?
must you be flocking?
must they be flocking? 	must I have flocked?
must you have flocked?
must she have flocked?
must we have flocked?
must you have flocked?
must they have flocked? 	must I have been flocking?
must you have been flocking?
must she have been flocking?
must we have been flocking?
must you have been flocking?
must they have been flocking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I flock?
mustn't you flock?
mustn't she flock?
mustn't we flock?
mustn't you flock?
mustn't they flock? 	mustn't I be flocking?
mustn't you be flocking?
mustn't she be flocking?
mustn't we be flocking?
mustn't you be flocking?
mustn't they be flocking? 	mustn't I have flocked?
mustn't you have flocked?
mustn't she have flocked?
mustn't we have flocked?
mustn't you have flocked?
mustn't they have flocked? 	mustn't I have been flocking?
mustn't you have been flocking?
mustn't she have been flocking?
mustn't we have been flocking?
mustn't you have been flocking?
mustn't they have been flocking?