I must cover you must cover she must cover we must cover you must cover they must cover
V-ing form
I must be covering you must be covering she must be covering we must be covering you must be covering they must be covering
Perfect
I must have covered you must have covered she must have covered we must have covered you must have covered they must have covered
V-ing perfect
I must have been covering you must have been covering she must have been covering we must have been covering you must have been covering they must have been covering
Negation
Simple form
I mustn't cover you mustn't cover she mustn't cover we mustn't cover you mustn't cover they mustn't cover
V-ing form
I mustn't be covering you mustn't be covering she mustn't be covering we mustn't be covering you mustn't be covering they mustn't be covering
Perfect
I mustn't have covered you mustn't have covered she mustn't have covered we mustn't have covered you mustn't have covered they mustn't have covered
V-ing perfect
I mustn't have been covering you mustn't have been covering she mustn't have been covering we mustn't have been covering you mustn't have been covering they mustn't have been covering
Interrogative form
Simple form
must I cover? must you cover? must she cover? must we cover? must you cover? must they cover?
V-ing form
must I be covering? must you be covering? must she be covering? must we be covering? must you be covering? must they be covering?
Perfect
must I have covered? must you have covered? must she have covered? must we have covered? must you have covered? must they have covered?
V-ing perfect
must I have been covering? must you have been covering? must she have been covering? must we have been covering? must you have been covering? must they have been covering?
Interro-negative form
Simple form
mustn't I cover? mustn't you cover? mustn't she cover? mustn't we cover? mustn't you cover? mustn't they cover?
V-ing form
mustn't I be covering? mustn't you be covering? mustn't she be covering? mustn't we be covering? mustn't you be covering? mustn't they be covering?
Perfect
mustn't I have covered? mustn't you have covered? mustn't she have covered? mustn't we have covered? mustn't you have covered? mustn't they have covered?
V-ing perfect
mustn't I have been covering? mustn't you have been covering? mustn't she have been covering? mustn't we have been covering? mustn't you have been covering? mustn't they have been covering?