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