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