must gnaw
Regular verb: gnaw - gnawed- gnawed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must gnaw
you must gnaw
he must gnaw
we must gnaw
you must gnaw
they must gnaw 	I must be gnawing
you must be gnawing
he must be gnawing
we must be gnawing
you must be gnawing
they must be gnawing	I must have gnawed
you must have gnawed
he must have gnawed
we must have gnawed
you must have gnawed
they must have gnawed	I must have been gnawing
you must have been gnawing
he must have been gnawing
we must have been gnawing
you must have been gnawing
they must have been gnawing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't gnaw
you mustn't gnaw
he mustn't gnaw
we mustn't gnaw
you mustn't gnaw
they mustn't gnaw 	I mustn't be gnawing
you mustn't be gnawing
he mustn't be gnawing
we mustn't be gnawing
you mustn't be gnawing
they mustn't be gnawing	I mustn't have gnawed
you mustn't have gnawed
he mustn't have gnawed
we mustn't have gnawed
you mustn't have gnawed
they mustn't have gnawed	I mustn't have been gnawing
you mustn't have been gnawing
he mustn't have been gnawing
we mustn't have been gnawing
you mustn't have been gnawing
they mustn't have been gnawing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I gnaw?
must you gnaw?
must he gnaw?
must we gnaw?
must you gnaw?
must they gnaw? 	must I be gnawing?
must you be gnawing?
must he be gnawing?
must we be gnawing?
must you be gnawing?
must they be gnawing? 	must I have gnawed?
must you have gnawed?
must he have gnawed?
must we have gnawed?
must you have gnawed?
must they have gnawed? 	must I have been gnawing?
must you have been gnawing?
must he have been gnawing?
must we have been gnawing?
must you have been gnawing?
must they have been gnawing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I gnaw?
mustn't you gnaw?
mustn't he gnaw?
mustn't we gnaw?
mustn't you gnaw?
mustn't they gnaw? 	mustn't I be gnawing?
mustn't you be gnawing?
mustn't he be gnawing?
mustn't we be gnawing?
mustn't you be gnawing?
mustn't they be gnawing? 	mustn't I have gnawed?
mustn't you have gnawed?
mustn't he have gnawed?
mustn't we have gnawed?
mustn't you have gnawed?
mustn't they have gnawed? 	mustn't I have been gnawing?
mustn't you have been gnawing?
mustn't he have been gnawing?
mustn't we have been gnawing?
mustn't you have been gnawing?
mustn't they have been gnawing?