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