must shell
Regular verb: shell - shelled- shelled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must shell
you must shell
she must shell
we must shell
you must shell
they must shell 	I must be shelling
you must be shelling
she must be shelling
we must be shelling
you must be shelling
they must be shelling	I must have shelled
you must have shelled
she must have shelled
we must have shelled
you must have shelled
they must have shelled	I must have been shelling
you must have been shelling
she must have been shelling
we must have been shelling
you must have been shelling
they must have been shelling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't shell
you mustn't shell
she mustn't shell
we mustn't shell
you mustn't shell
they mustn't shell 	I mustn't be shelling
you mustn't be shelling
she mustn't be shelling
we mustn't be shelling
you mustn't be shelling
they mustn't be shelling	I mustn't have shelled
you mustn't have shelled
she mustn't have shelled
we mustn't have shelled
you mustn't have shelled
they mustn't have shelled	I mustn't have been shelling
you mustn't have been shelling
she mustn't have been shelling
we mustn't have been shelling
you mustn't have been shelling
they mustn't have been shelling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I shell?
must you shell?
must she shell?
must we shell?
must you shell?
must they shell? 	must I be shelling?
must you be shelling?
must she be shelling?
must we be shelling?
must you be shelling?
must they be shelling? 	must I have shelled?
must you have shelled?
must she have shelled?
must we have shelled?
must you have shelled?
must they have shelled? 	must I have been shelling?
must you have been shelling?
must she have been shelling?
must we have been shelling?
must you have been shelling?
must they have been shelling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I shell?
mustn't you shell?
mustn't she shell?
mustn't we shell?
mustn't you shell?
mustn't they shell? 	mustn't I be shelling?
mustn't you be shelling?
mustn't she be shelling?
mustn't we be shelling?
mustn't you be shelling?
mustn't they be shelling? 	mustn't I have shelled?
mustn't you have shelled?
mustn't she have shelled?
mustn't we have shelled?
mustn't you have shelled?
mustn't they have shelled? 	mustn't I have been shelling?
mustn't you have been shelling?
mustn't she have been shelling?
mustn't we have been shelling?
mustn't you have been shelling?
mustn't they have been shelling?