I must decelerate you must decelerate he must decelerate we must decelerate you must decelerate they must decelerate
V-ing form
I must be decelerating you must be decelerating he must be decelerating we must be decelerating you must be decelerating they must be decelerating
Perfect
I must have decelerated you must have decelerated he must have decelerated we must have decelerated you must have decelerated they must have decelerated
V-ing perfect
I must have been decelerating you must have been decelerating he must have been decelerating we must have been decelerating you must have been decelerating they must have been decelerating
Negation
Simple form
I mustn't decelerate you mustn't decelerate he mustn't decelerate we mustn't decelerate you mustn't decelerate they mustn't decelerate
V-ing form
I mustn't be decelerating you mustn't be decelerating he mustn't be decelerating we mustn't be decelerating you mustn't be decelerating they mustn't be decelerating
Perfect
I mustn't have decelerated you mustn't have decelerated he mustn't have decelerated we mustn't have decelerated you mustn't have decelerated they mustn't have decelerated
V-ing perfect
I mustn't have been decelerating you mustn't have been decelerating he mustn't have been decelerating we mustn't have been decelerating you mustn't have been decelerating they mustn't have been decelerating
Interrogative form
Simple form
must I decelerate? must you decelerate? must he decelerate? must we decelerate? must you decelerate? must they decelerate?
V-ing form
must I be decelerating? must you be decelerating? must he be decelerating? must we be decelerating? must you be decelerating? must they be decelerating?
Perfect
must I have decelerated? must you have decelerated? must he have decelerated? must we have decelerated? must you have decelerated? must they have decelerated?
V-ing perfect
must I have been decelerating? must you have been decelerating? must he have been decelerating? must we have been decelerating? must you have been decelerating? must they have been decelerating?
Interro-negative form
Simple form
mustn't I decelerate? mustn't you decelerate? mustn't he decelerate? mustn't we decelerate? mustn't you decelerate? mustn't they decelerate?
V-ing form
mustn't I be decelerating? mustn't you be decelerating? mustn't he be decelerating? mustn't we be decelerating? mustn't you be decelerating? mustn't they be decelerating?
Perfect
mustn't I have decelerated? mustn't you have decelerated? mustn't he have decelerated? mustn't we have decelerated? mustn't you have decelerated? mustn't they have decelerated?
V-ing perfect
mustn't I have been decelerating? mustn't you have been decelerating? mustn't he have been decelerating? mustn't we have been decelerating? mustn't you have been decelerating? mustn't they have been decelerating?