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