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 must not build you must not build he must not build we must not build you must not build they must not build
V-ing form
I must not be building you must not be building he must not be building we must not be building you must not be building they must not be building
Perfect
I must not have built you must not have built he must not have built we must not have built you must not have built they must not have built
V-ing perfect
I must not have been building you must not have been building he must not have been building we must not have been building you must not have been building they must not 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
must I not build? must you not build? must he not build? must we not build? must you not build? must they not build?
V-ing form
must I not be building? must you not be building? must he not be building? must we not be building? must you not be building? must they not be building?
Perfect
must I not have built? must you not have built? must he not have built? must we not have built? must you not have built? must they not have built?
V-ing perfect
must I not have been building? must you not have been building? must he not have been building? must we not have been building? must you not have been building? must they not have been building?