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