I must teach you must teach she must teach we must teach you must teach they must teach
V-ing form
I must be teaching you must be teaching she must be teaching we must be teaching you must be teaching they must be teaching
Perfect
I must have taught you must have taught she must have taught we must have taught you must have taught they must have taught
V-ing perfect
I must have been teaching you must have been teaching she must have been teaching we must have been teaching you must have been teaching they must have been teaching
Negation
Simple form
I must not teach you must not teach she must not teach we must not teach you must not teach they must not teach
V-ing form
I must not be teaching you must not be teaching she must not be teaching we must not be teaching you must not be teaching they must not be teaching
Perfect
I must not have taught you must not have taught she must not have taught we must not have taught you must not have taught they must not have taught
V-ing perfect
I must not have been teaching you must not have been teaching she must not have been teaching we must not have been teaching you must not have been teaching they must not have been teaching
Interrogative form
Simple form
must I teach? must you teach? must she teach? must we teach? must you teach? must they teach?
V-ing form
must I be teaching? must you be teaching? must she be teaching? must we be teaching? must you be teaching? must they be teaching?
Perfect
must I have taught? must you have taught? must she have taught? must we have taught? must you have taught? must they have taught?
V-ing perfect
must I have been teaching? must you have been teaching? must she have been teaching? must we have been teaching? must you have been teaching? must they have been teaching?
Interro-negative form
Simple form
must I not teach? must you not teach? must she not teach? must we not teach? must you not teach? must they not teach?
V-ing form
must I not be teaching? must you not be teaching? must she not be teaching? must we not be teaching? must you not be teaching? must they not be teaching?
Perfect
must I not have taught? must you not have taught? must she not have taught? must we not have taught? must you not have taught? must they not have taught?
V-ing perfect
must I not have been teaching? must you not have been teaching? must she not have been teaching? must we not have been teaching? must you not have been teaching? must they not have been teaching?