must screw
Regular verb: screw - screwed- screwed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must screw
you must screw
she must screw
we must screw
you must screw
they must screw 	I must be screwing
you must be screwing
she must be screwing
we must be screwing
you must be screwing
they must be screwing	I must have screwed
you must have screwed
she must have screwed
we must have screwed
you must have screwed
they must have screwed	I must have been screwing
you must have been screwing
she must have been screwing
we must have been screwing
you must have been screwing
they must have been screwing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not screw
you must not screw
she must not screw
we must not screw
you must not screw
they must not screw 	I must not be screwing
you must not be screwing
she must not be screwing
we must not be screwing
you must not be screwing
they must not be screwing	I must not have screwed
you must not have screwed
she must not have screwed
we must not have screwed
you must not have screwed
they must not have screwed	I must not have been screwing
you must not have been screwing
she must not have been screwing
we must not have been screwing
you must not have been screwing
they must not have been screwing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I screw?
must you screw?
must she screw?
must we screw?
must you screw?
must they screw? 	must I be screwing?
must you be screwing?
must she be screwing?
must we be screwing?
must you be screwing?
must they be screwing? 	must I have screwed?
must you have screwed?
must she have screwed?
must we have screwed?
must you have screwed?
must they have screwed? 	must I have been screwing?
must you have been screwing?
must she have been screwing?
must we have been screwing?
must you have been screwing?
must they have been screwing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not screw?
must you not screw?
must she not screw?
must we not screw?
must you not screw?
must they not screw? 	must I not be screwing?
must you not be screwing?
must she not be screwing?
must we not be screwing?
must you not be screwing?
must they not be screwing? 	must I not have screwed?
must you not have screwed?
must she not have screwed?
must we not have screwed?
must you not have screwed?
must they not have screwed? 	must I not have been screwing?
must you not have been screwing?
must she not have been screwing?
must we not have been screwing?
must you not have been screwing?
must they not have been screwing?