must believe
Regular verb: believe - believed- believed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must believe
you must believe
she must believe
we must believe
you must believe
they must believe 	I must be believing
you must be believing
she must be believing
we must be believing
you must be believing
they must be believing	I must have believed
you must have believed
she must have believed
we must have believed
you must have believed
they must have believed	I must have been believing
you must have been believing
she must have been believing
we must have been believing
you must have been believing
they must have been believing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't believe
you mustn't believe
she mustn't believe
we mustn't believe
you mustn't believe
they mustn't believe 	I mustn't be believing
you mustn't be believing
she mustn't be believing
we mustn't be believing
you mustn't be believing
they mustn't be believing	I mustn't have believed
you mustn't have believed
she mustn't have believed
we mustn't have believed
you mustn't have believed
they mustn't have believed	I mustn't have been believing
you mustn't have been believing
she mustn't have been believing
we mustn't have been believing
you mustn't have been believing
they mustn't have been believing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I believe?
must you believe?
must she believe?
must we believe?
must you believe?
must they believe? 	must I be believing?
must you be believing?
must she be believing?
must we be believing?
must you be believing?
must they be believing? 	must I have believed?
must you have believed?
must she have believed?
must we have believed?
must you have believed?
must they have believed? 	must I have been believing?
must you have been believing?
must she have been believing?
must we have been believing?
must you have been believing?
must they have been believing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I believe?
mustn't you believe?
mustn't she believe?
mustn't we believe?
mustn't you believe?
mustn't they believe? 	mustn't I be believing?
mustn't you be believing?
mustn't she be believing?
mustn't we be believing?
mustn't you be believing?
mustn't they be believing? 	mustn't I have believed?
mustn't you have believed?
mustn't she have believed?
mustn't we have believed?
mustn't you have believed?
mustn't they have believed? 	mustn't I have been believing?
mustn't you have been believing?
mustn't she have been believing?
mustn't we have been believing?
mustn't you have been believing?
mustn't they have been believing?