I must step you must step she must step we must step you must step they must step
V-ing form
I must be stepping you must be stepping she must be stepping we must be stepping you must be stepping they must be stepping
Perfect
I must have stepped you must have stepped she must have stepped we must have stepped you must have stepped they must have stepped
V-ing perfect
I must have been stepping you must have been stepping she must have been stepping we must have been stepping you must have been stepping they must have been stepping
Negation
Simple form
I must not step you must not step she must not step we must not step you must not step they must not step
V-ing form
I must not be stepping you must not be stepping she must not be stepping we must not be stepping you must not be stepping they must not be stepping
Perfect
I must not have stepped you must not have stepped she must not have stepped we must not have stepped you must not have stepped they must not have stepped
V-ing perfect
I must not have been stepping you must not have been stepping she must not have been stepping we must not have been stepping you must not have been stepping they must not have been stepping
Interrogative form
Simple form
must I step? must you step? must she step? must we step? must you step? must they step?
V-ing form
must I be stepping? must you be stepping? must she be stepping? must we be stepping? must you be stepping? must they be stepping?
Perfect
must I have stepped? must you have stepped? must she have stepped? must we have stepped? must you have stepped? must they have stepped?
V-ing perfect
must I have been stepping? must you have been stepping? must she have been stepping? must we have been stepping? must you have been stepping? must they have been stepping?
Interro-negative form
Simple form
must I not step? must you not step? must she not step? must we not step? must you not step? must they not step?
V-ing form
must I not be stepping? must you not be stepping? must she not be stepping? must we not be stepping? must you not be stepping? must they not be stepping?
Perfect
must I not have stepped? must you not have stepped? must she not have stepped? must we not have stepped? must you not have stepped? must they not have stepped?
V-ing perfect
must I not have been stepping? must you not have been stepping? must she not have been stepping? must we not have been stepping? must you not have been stepping? must they not have been stepping?