I must cover you must cover he must cover we must cover you must cover they must cover
V-ing form
I must be covering you must be covering he must be covering we must be covering you must be covering they must be covering
Perfect
I must have covered you must have covered he 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 he 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 he 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 he 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 he 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 he 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 he cover? must we cover? must you cover? must they cover?
V-ing form
must I be covering? must you be covering? must he be covering? must we be covering? must you be covering? must they be covering?
Perfect
must I have covered? must you have covered? must he 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 he 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 he 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 he 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 he 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 he have been covering? mustn't we have been covering? mustn't you have been covering? mustn't they have been covering?