I must smooth you must smooth she must smooth we must smooth you must smooth they must smooth
V-ing form
I must be smoothing you must be smoothing she must be smoothing we must be smoothing you must be smoothing they must be smoothing
Perfect
I must have smoothed you must have smoothed she 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 she 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 she 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 she 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 she 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 she 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 she smooth? must we smooth? must you smooth? must they smooth?
V-ing form
must I be smoothing? must you be smoothing? must she be smoothing? must we be smoothing? must you be smoothing? must they be smoothing?
Perfect
must I have smoothed? must you have smoothed? must she 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 she 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 she 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 she 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 she 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 she have been smoothing? mustn't we have been smoothing? mustn't you have been smoothing? mustn't they have been smoothing?