I must build you must build she must build we must build you must build they must build
V-ing form
I must be building you must be building she must be building we must be building you must be building they must be building
Perfect
I must have built you must have built she 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 she 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 she 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 she 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 she 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 she 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 she build? must we build? must you build? must they build?
V-ing form
must I be building? must you be building? must she be building? must we be building? must you be building? must they be building?
Perfect
must I have built? must you have built? must she 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 she 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 she 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 she 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 she 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 she have been building? mustn't we have been building? mustn't you have been building? mustn't they have been building?