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 mustn't screw
you mustn't screw
she mustn't screw
we mustn't screw
you mustn't screw
they mustn't screw 	I mustn't be screwing
you mustn't be screwing
she mustn't be screwing
we mustn't be screwing
you mustn't be screwing
they mustn't be screwing	I mustn't have screwed
you mustn't have screwed
she mustn't have screwed
we mustn't have screwed
you mustn't have screwed
they mustn't have screwed	I mustn't have been screwing
you mustn't have been screwing
she mustn't have been screwing
we mustn't have been screwing
you mustn't have been screwing
they mustn't 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 	
mustn't I screw?
mustn't you screw?
mustn't she screw?
mustn't we screw?
mustn't you screw?
mustn't they screw? 	mustn't I be screwing?
mustn't you be screwing?
mustn't she be screwing?
mustn't we be screwing?
mustn't you be screwing?
mustn't they be screwing? 	mustn't I have screwed?
mustn't you have screwed?
mustn't she have screwed?
mustn't we have screwed?
mustn't you have screwed?
mustn't they have screwed? 	mustn't I have been screwing?
mustn't you have been screwing?
mustn't she have been screwing?
mustn't we have been screwing?
mustn't you have been screwing?
mustn't they have been screwing?