must cow
Regular verb: cow - cowed- cowed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must cow
you must cow
he must cow
we must cow
you must cow
they must cow 	I must be cowing
you must be cowing
he must be cowing
we must be cowing
you must be cowing
they must be cowing	I must have cowed
you must have cowed
he must have cowed
we must have cowed
you must have cowed
they must have cowed	I must have been cowing
you must have been cowing
he must have been cowing
we must have been cowing
you must have been cowing
they must have been cowing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't cow
you mustn't cow
he mustn't cow
we mustn't cow
you mustn't cow
they mustn't cow 	I mustn't be cowing
you mustn't be cowing
he mustn't be cowing
we mustn't be cowing
you mustn't be cowing
they mustn't be cowing	I mustn't have cowed
you mustn't have cowed
he mustn't have cowed
we mustn't have cowed
you mustn't have cowed
they mustn't have cowed	I mustn't have been cowing
you mustn't have been cowing
he mustn't have been cowing
we mustn't have been cowing
you mustn't have been cowing
they mustn't have been cowing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I cow?
must you cow?
must he cow?
must we cow?
must you cow?
must they cow? 	must I be cowing?
must you be cowing?
must he be cowing?
must we be cowing?
must you be cowing?
must they be cowing? 	must I have cowed?
must you have cowed?
must he have cowed?
must we have cowed?
must you have cowed?
must they have cowed? 	must I have been cowing?
must you have been cowing?
must he have been cowing?
must we have been cowing?
must you have been cowing?
must they have been cowing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I cow?
mustn't you cow?
mustn't he cow?
mustn't we cow?
mustn't you cow?
mustn't they cow? 	mustn't I be cowing?
mustn't you be cowing?
mustn't he be cowing?
mustn't we be cowing?
mustn't you be cowing?
mustn't they be cowing? 	mustn't I have cowed?
mustn't you have cowed?
mustn't he have cowed?
mustn't we have cowed?
mustn't you have cowed?
mustn't they have cowed? 	mustn't I have been cowing?
mustn't you have been cowing?
mustn't he have been cowing?
mustn't we have been cowing?
mustn't you have been cowing?
mustn't they have been cowing?