I must feed you must feed she must feed we must feed you must feed they must feed
V-ing form
I must be feeding you must be feeding she must be feeding we must be feeding you must be feeding they must be feeding
Perfect
I must have fed you must have fed she 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 she 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 she 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 she 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 she 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 she 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 she feed? must we feed? must you feed? must they feed?
V-ing form
must I be feeding? must you be feeding? must she be feeding? must we be feeding? must you be feeding? must they be feeding?
Perfect
must I have fed? must you have fed? must she 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 she 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 she 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 she 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 she 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 she have been feeding? mustn't we have been feeding? mustn't you have been feeding? mustn't they have been feeding?