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