must burrow
Regular verb: burrow - burrowed- burrowed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must burrow
you must burrow
she must burrow
we must burrow
you must burrow
they must burrow 	I must be burrowing
you must be burrowing
she must be burrowing
we must be burrowing
you must be burrowing
they must be burrowing	I must have burrowed
you must have burrowed
she must have burrowed
we must have burrowed
you must have burrowed
they must have burrowed	I must have been burrowing
you must have been burrowing
she must have been burrowing
we must have been burrowing
you must have been burrowing
they must have been burrowing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not burrow
you must not burrow
she must not burrow
we must not burrow
you must not burrow
they must not burrow 	I must not be burrowing
you must not be burrowing
she must not be burrowing
we must not be burrowing
you must not be burrowing
they must not be burrowing	I must not have burrowed
you must not have burrowed
she must not have burrowed
we must not have burrowed
you must not have burrowed
they must not have burrowed	I must not have been burrowing
you must not have been burrowing
she must not have been burrowing
we must not have been burrowing
you must not have been burrowing
they must not have been burrowing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I burrow?
must you burrow?
must she burrow?
must we burrow?
must you burrow?
must they burrow? 	must I be burrowing?
must you be burrowing?
must she be burrowing?
must we be burrowing?
must you be burrowing?
must they be burrowing? 	must I have burrowed?
must you have burrowed?
must she have burrowed?
must we have burrowed?
must you have burrowed?
must they have burrowed? 	must I have been burrowing?
must you have been burrowing?
must she have been burrowing?
must we have been burrowing?
must you have been burrowing?
must they have been burrowing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not burrow?
must you not burrow?
must she not burrow?
must we not burrow?
must you not burrow?
must they not burrow? 	must I not be burrowing?
must you not be burrowing?
must she not be burrowing?
must we not be burrowing?
must you not be burrowing?
must they not be burrowing? 	must I not have burrowed?
must you not have burrowed?
must she not have burrowed?
must we not have burrowed?
must you not have burrowed?
must they not have burrowed? 	must I not have been burrowing?
must you not have been burrowing?
must she not have been burrowing?
must we not have been burrowing?
must you not have been burrowing?
must they not have been burrowing?