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