must corkscrew
Regular verb: corkscrew - corkscrewed- corkscrewed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must corkscrew
you must corkscrew
she must corkscrew
we must corkscrew
you must corkscrew
they must corkscrew 	I must be corkscrewing
you must be corkscrewing
she must be corkscrewing
we must be corkscrewing
you must be corkscrewing
they must be corkscrewing	I must have corkscrewed
you must have corkscrewed
she must have corkscrewed
we must have corkscrewed
you must have corkscrewed
they must have corkscrewed	I must have been corkscrewing
you must have been corkscrewing
she must have been corkscrewing
we must have been corkscrewing
you must have been corkscrewing
they must have been corkscrewing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't corkscrew
you mustn't corkscrew
she mustn't corkscrew
we mustn't corkscrew
you mustn't corkscrew
they mustn't corkscrew 	I mustn't be corkscrewing
you mustn't be corkscrewing
she mustn't be corkscrewing
we mustn't be corkscrewing
you mustn't be corkscrewing
they mustn't be corkscrewing	I mustn't have corkscrewed
you mustn't have corkscrewed
she mustn't have corkscrewed
we mustn't have corkscrewed
you mustn't have corkscrewed
they mustn't have corkscrewed	I mustn't have been corkscrewing
you mustn't have been corkscrewing
she mustn't have been corkscrewing
we mustn't have been corkscrewing
you mustn't have been corkscrewing
they mustn't have been corkscrewing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I corkscrew?
must you corkscrew?
must she corkscrew?
must we corkscrew?
must you corkscrew?
must they corkscrew? 	must I be corkscrewing?
must you be corkscrewing?
must she be corkscrewing?
must we be corkscrewing?
must you be corkscrewing?
must they be corkscrewing? 	must I have corkscrewed?
must you have corkscrewed?
must she have corkscrewed?
must we have corkscrewed?
must you have corkscrewed?
must they have corkscrewed? 	must I have been corkscrewing?
must you have been corkscrewing?
must she have been corkscrewing?
must we have been corkscrewing?
must you have been corkscrewing?
must they have been corkscrewing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I corkscrew?
mustn't you corkscrew?
mustn't she corkscrew?
mustn't we corkscrew?
mustn't you corkscrew?
mustn't they corkscrew? 	mustn't I be corkscrewing?
mustn't you be corkscrewing?
mustn't she be corkscrewing?
mustn't we be corkscrewing?
mustn't you be corkscrewing?
mustn't they be corkscrewing? 	mustn't I have corkscrewed?
mustn't you have corkscrewed?
mustn't she have corkscrewed?
mustn't we have corkscrewed?
mustn't you have corkscrewed?
mustn't they have corkscrewed? 	mustn't I have been corkscrewing?
mustn't you have been corkscrewing?
mustn't she have been corkscrewing?
mustn't we have been corkscrewing?
mustn't you have been corkscrewing?
mustn't they have been corkscrewing?