I must engulf you must engulf she must engulf we must engulf you must engulf they must engulf
V-ing form
I must be engulfing you must be engulfing she must be engulfing we must be engulfing you must be engulfing they must be engulfing
Perfect
I must have engulfed you must have engulfed she must have engulfed we must have engulfed you must have engulfed they must have engulfed
V-ing perfect
I must have been engulfing you must have been engulfing she must have been engulfing we must have been engulfing you must have been engulfing they must have been engulfing
Negation
Simple form
I must not engulf you must not engulf she must not engulf we must not engulf you must not engulf they must not engulf
V-ing form
I must not be engulfing you must not be engulfing she must not be engulfing we must not be engulfing you must not be engulfing they must not be engulfing
Perfect
I must not have engulfed you must not have engulfed she must not have engulfed we must not have engulfed you must not have engulfed they must not have engulfed
V-ing perfect
I must not have been engulfing you must not have been engulfing she must not have been engulfing we must not have been engulfing you must not have been engulfing they must not have been engulfing
Interrogative form
Simple form
must I engulf? must you engulf? must she engulf? must we engulf? must you engulf? must they engulf?
V-ing form
must I be engulfing? must you be engulfing? must she be engulfing? must we be engulfing? must you be engulfing? must they be engulfing?
Perfect
must I have engulfed? must you have engulfed? must she have engulfed? must we have engulfed? must you have engulfed? must they have engulfed?
V-ing perfect
must I have been engulfing? must you have been engulfing? must she have been engulfing? must we have been engulfing? must you have been engulfing? must they have been engulfing?
Interro-negative form
Simple form
must I not engulf? must you not engulf? must she not engulf? must we not engulf? must you not engulf? must they not engulf?
V-ing form
must I not be engulfing? must you not be engulfing? must she not be engulfing? must we not be engulfing? must you not be engulfing? must they not be engulfing?
Perfect
must I not have engulfed? must you not have engulfed? must she not have engulfed? must we not have engulfed? must you not have engulfed? must they not have engulfed?
V-ing perfect
must I not have been engulfing? must you not have been engulfing? must she not have been engulfing? must we not have been engulfing? must you not have been engulfing? must they not have been engulfing?