I must unmask you must unmask she must unmask we must unmask you must unmask they must unmask
V-ing form
I must be unmasking you must be unmasking she must be unmasking we must be unmasking you must be unmasking they must be unmasking
Perfect
I must have unmasked you must have unmasked she must have unmasked we must have unmasked you must have unmasked they must have unmasked
V-ing perfect
I must have been unmasking you must have been unmasking she must have been unmasking we must have been unmasking you must have been unmasking they must have been unmasking
Negation
Simple form
I mustn't unmask you mustn't unmask she mustn't unmask we mustn't unmask you mustn't unmask they mustn't unmask
V-ing form
I mustn't be unmasking you mustn't be unmasking she mustn't be unmasking we mustn't be unmasking you mustn't be unmasking they mustn't be unmasking
Perfect
I mustn't have unmasked you mustn't have unmasked she mustn't have unmasked we mustn't have unmasked you mustn't have unmasked they mustn't have unmasked
V-ing perfect
I mustn't have been unmasking you mustn't have been unmasking she mustn't have been unmasking we mustn't have been unmasking you mustn't have been unmasking they mustn't have been unmasking
Interrogative form
Simple form
must I unmask? must you unmask? must she unmask? must we unmask? must you unmask? must they unmask?
V-ing form
must I be unmasking? must you be unmasking? must she be unmasking? must we be unmasking? must you be unmasking? must they be unmasking?
Perfect
must I have unmasked? must you have unmasked? must she have unmasked? must we have unmasked? must you have unmasked? must they have unmasked?
V-ing perfect
must I have been unmasking? must you have been unmasking? must she have been unmasking? must we have been unmasking? must you have been unmasking? must they have been unmasking?
Interro-negative form
Simple form
mustn't I unmask? mustn't you unmask? mustn't she unmask? mustn't we unmask? mustn't you unmask? mustn't they unmask?
V-ing form
mustn't I be unmasking? mustn't you be unmasking? mustn't she be unmasking? mustn't we be unmasking? mustn't you be unmasking? mustn't they be unmasking?
Perfect
mustn't I have unmasked? mustn't you have unmasked? mustn't she have unmasked? mustn't we have unmasked? mustn't you have unmasked? mustn't they have unmasked?
V-ing perfect
mustn't I have been unmasking? mustn't you have been unmasking? mustn't she have been unmasking? mustn't we have been unmasking? mustn't you have been unmasking? mustn't they have been unmasking?