I must burn you must burn he must burn we must burn you must burn they must burn
V-ing form
I must be burning you must be burning he must be burning we must be burning you must be burning they must be burning
Perfect
I must have burned you must have burned he must have burned we must have burned you must have burned they must have burned
V-ing perfect
I must have been burning you must have been burning he must have been burning we must have been burning you must have been burning they must have been burning
Negation
Simple form
I must not burn you must not burn he must not burn we must not burn you must not burn they must not burn
V-ing form
I must not be burning you must not be burning he must not be burning we must not be burning you must not be burning they must not be burning
Perfect
I must not have burned you must not have burned he must not have burned we must not have burned you must not have burned they must not have burned
V-ing perfect
I must not have been burning you must not have been burning he must not have been burning we must not have been burning you must not have been burning they must not have been burning
Interrogative form
Simple form
must I burn? must you burn? must he burn? must we burn? must you burn? must they burn?
V-ing form
must I be burning? must you be burning? must he be burning? must we be burning? must you be burning? must they be burning?
Perfect
must I have burned? must you have burned? must he have burned? must we have burned? must you have burned? must they have burned?
V-ing perfect
must I have been burning? must you have been burning? must he have been burning? must we have been burning? must you have been burning? must they have been burning?
Interro-negative form
Simple form
must I not burn? must you not burn? must he not burn? must we not burn? must you not burn? must they not burn?
V-ing form
must I not be burning? must you not be burning? must he not be burning? must we not be burning? must you not be burning? must they not be burning?
Perfect
must I not have burned? must you not have burned? must he not have burned? must we not have burned? must you not have burned? must they not have burned?
V-ing perfect
must I not have been burning? must you not have been burning? must he not have been burning? must we not have been burning? must you not have been burning? must they not have been burning?