must mast
Regular verb: mast - masted- masted

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must mast
you must mast
she must mast
we must mast
you must mast
they must mast 	I must be masting
you must be masting
she must be masting
we must be masting
you must be masting
they must be masting	I must have masted
you must have masted
she must have masted
we must have masted
you must have masted
they must have masted	I must have been masting
you must have been masting
she must have been masting
we must have been masting
you must have been masting
they must have been masting	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not mast
you must not mast
she must not mast
we must not mast
you must not mast
they must not mast 	I must not be masting
you must not be masting
she must not be masting
we must not be masting
you must not be masting
they must not be masting	I must not have masted
you must not have masted
she must not have masted
we must not have masted
you must not have masted
they must not have masted	I must not have been masting
you must not have been masting
she must not have been masting
we must not have been masting
you must not have been masting
they must not have been masting	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I mast?
must you mast?
must she mast?
must we mast?
must you mast?
must they mast? 	must I be masting?
must you be masting?
must she be masting?
must we be masting?
must you be masting?
must they be masting? 	must I have masted?
must you have masted?
must she have masted?
must we have masted?
must you have masted?
must they have masted? 	must I have been masting?
must you have been masting?
must she have been masting?
must we have been masting?
must you have been masting?
must they have been masting? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not mast?
must you not mast?
must she not mast?
must we not mast?
must you not mast?
must they not mast? 	must I not be masting?
must you not be masting?
must she not be masting?
must we not be masting?
must you not be masting?
must they not be masting? 	must I not have masted?
must you not have masted?
must she not have masted?
must we not have masted?
must you not have masted?
must they not have masted? 	must I not have been masting?
must you not have been masting?
must she not have been masting?
must we not have been masting?
must you not have been masting?
must they not have been masting?