must tusk
Regular verb: tusk - tusked- tusked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must tusk
you must tusk
he must tusk
we must tusk
you must tusk
they must tusk 	I must be tusking
you must be tusking
he must be tusking
we must be tusking
you must be tusking
they must be tusking	I must have tusked
you must have tusked
he must have tusked
we must have tusked
you must have tusked
they must have tusked	I must have been tusking
you must have been tusking
he must have been tusking
we must have been tusking
you must have been tusking
they must have been tusking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not tusk
you must not tusk
he must not tusk
we must not tusk
you must not tusk
they must not tusk 	I must not be tusking
you must not be tusking
he must not be tusking
we must not be tusking
you must not be tusking
they must not be tusking	I must not have tusked
you must not have tusked
he must not have tusked
we must not have tusked
you must not have tusked
they must not have tusked	I must not have been tusking
you must not have been tusking
he must not have been tusking
we must not have been tusking
you must not have been tusking
they must not have been tusking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I tusk?
must you tusk?
must he tusk?
must we tusk?
must you tusk?
must they tusk? 	must I be tusking?
must you be tusking?
must he be tusking?
must we be tusking?
must you be tusking?
must they be tusking? 	must I have tusked?
must you have tusked?
must he have tusked?
must we have tusked?
must you have tusked?
must they have tusked? 	must I have been tusking?
must you have been tusking?
must he have been tusking?
must we have been tusking?
must you have been tusking?
must they have been tusking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not tusk?
must you not tusk?
must he not tusk?
must we not tusk?
must you not tusk?
must they not tusk? 	must I not be tusking?
must you not be tusking?
must he not be tusking?
must we not be tusking?
must you not be tusking?
must they not be tusking? 	must I not have tusked?
must you not have tusked?
must he not have tusked?
must we not have tusked?
must you not have tusked?
must they not have tusked? 	must I not have been tusking?
must you not have been tusking?
must he not have been tusking?
must we not have been tusking?
must you not have been tusking?
must they not have been tusking?