I must stamp you must stamp he must stamp we must stamp you must stamp they must stamp
V-ing form
I must be stamping you must be stamping he must be stamping we must be stamping you must be stamping they must be stamping
Perfect
I must have stamped you must have stamped he 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 he must have been stamping we must have been stamping you must have been stamping they must have been stamping
Negation
Simple form
I must not stamp you must not stamp he must not stamp we must not stamp you must not stamp they must not stamp
V-ing form
I must not be stamping you must not be stamping he must not be stamping we must not be stamping you must not be stamping they must not be stamping
Perfect
I must not have stamped you must not have stamped he must not have stamped we must not have stamped you must not have stamped they must not have stamped
V-ing perfect
I must not have been stamping you must not have been stamping he must not have been stamping we must not have been stamping you must not have been stamping they must not have been stamping
Interrogative form
Simple form
must I stamp? must you stamp? must he stamp? must we stamp? must you stamp? must they stamp?
V-ing form
must I be stamping? must you be stamping? must he be stamping? must we be stamping? must you be stamping? must they be stamping?
Perfect
must I have stamped? must you have stamped? must he 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 he have been stamping? must we have been stamping? must you have been stamping? must they have been stamping?
Interro-negative form
Simple form
must I not stamp? must you not stamp? must he not stamp? must we not stamp? must you not stamp? must they not stamp?
V-ing form
must I not be stamping? must you not be stamping? must he not be stamping? must we not be stamping? must you not be stamping? must they not be stamping?
Perfect
must I not have stamped? must you not have stamped? must he not have stamped? must we not have stamped? must you not have stamped? must they not have stamped?
V-ing perfect
must I not have been stamping? must you not have been stamping? must he not have been stamping? must we not have been stamping? must you not have been stamping? must they not have been stamping?