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