I must melt you must melt she must melt we must melt you must melt they must melt
V-ing form
I must be melting you must be melting she must be melting we must be melting you must be melting they must be melting
Perfect
I must have melted you must have melted she must have melted we must have melted you must have melted they must have melted
V-ing perfect
I must have been melting you must have been melting she must have been melting we must have been melting you must have been melting they must have been melting
Negation
Simple form
I must not melt you must not melt she must not melt we must not melt you must not melt they must not melt
V-ing form
I must not be melting you must not be melting she must not be melting we must not be melting you must not be melting they must not be melting
Perfect
I must not have melted you must not have melted she must not have melted we must not have melted you must not have melted they must not have melted
V-ing perfect
I must not have been melting you must not have been melting she must not have been melting we must not have been melting you must not have been melting they must not have been melting
Interrogative form
Simple form
must I melt? must you melt? must she melt? must we melt? must you melt? must they melt?
V-ing form
must I be melting? must you be melting? must she be melting? must we be melting? must you be melting? must they be melting?
Perfect
must I have melted? must you have melted? must she have melted? must we have melted? must you have melted? must they have melted?
V-ing perfect
must I have been melting? must you have been melting? must she have been melting? must we have been melting? must you have been melting? must they have been melting?
Interro-negative form
Simple form
must I not melt? must you not melt? must she not melt? must we not melt? must you not melt? must they not melt?
V-ing form
must I not be melting? must you not be melting? must she not be melting? must we not be melting? must you not be melting? must they not be melting?
Perfect
must I not have melted? must you not have melted? must she not have melted? must we not have melted? must you not have melted? must they not have melted?
V-ing perfect
must I not have been melting? must you not have been melting? must she not have been melting? must we not have been melting? must you not have been melting? must they not have been melting?