I must fever you must fever he must fever we must fever you must fever they must fever
V-ing form
I must be fevering you must be fevering he must be fevering we must be fevering you must be fevering they must be fevering
Perfect
I must have fevered you must have fevered he must have fevered we must have fevered you must have fevered they must have fevered
V-ing perfect
I must have been fevering you must have been fevering he must have been fevering we must have been fevering you must have been fevering they must have been fevering
Negation
Simple form
I mustn't fever you mustn't fever he mustn't fever we mustn't fever you mustn't fever they mustn't fever
V-ing form
I mustn't be fevering you mustn't be fevering he mustn't be fevering we mustn't be fevering you mustn't be fevering they mustn't be fevering
Perfect
I mustn't have fevered you mustn't have fevered he mustn't have fevered we mustn't have fevered you mustn't have fevered they mustn't have fevered
V-ing perfect
I mustn't have been fevering you mustn't have been fevering he mustn't have been fevering we mustn't have been fevering you mustn't have been fevering they mustn't have been fevering
Interrogative form
Simple form
must I fever? must you fever? must he fever? must we fever? must you fever? must they fever?
V-ing form
must I be fevering? must you be fevering? must he be fevering? must we be fevering? must you be fevering? must they be fevering?
Perfect
must I have fevered? must you have fevered? must he have fevered? must we have fevered? must you have fevered? must they have fevered?
V-ing perfect
must I have been fevering? must you have been fevering? must he have been fevering? must we have been fevering? must you have been fevering? must they have been fevering?
Interro-negative form
Simple form
mustn't I fever? mustn't you fever? mustn't he fever? mustn't we fever? mustn't you fever? mustn't they fever?
V-ing form
mustn't I be fevering? mustn't you be fevering? mustn't he be fevering? mustn't we be fevering? mustn't you be fevering? mustn't they be fevering?
Perfect
mustn't I have fevered? mustn't you have fevered? mustn't he have fevered? mustn't we have fevered? mustn't you have fevered? mustn't they have fevered?
V-ing perfect
mustn't I have been fevering? mustn't you have been fevering? mustn't he have been fevering? mustn't we have been fevering? mustn't you have been fevering? mustn't they have been fevering?