must sin
Regular verb: sin - sinned- sinned

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must sin
you must sin
she must sin
we must sin
you must sin
they must sin 	I must be sinning
you must be sinning
she must be sinning
we must be sinning
you must be sinning
they must be sinning	I must have sinned
you must have sinned
she must have sinned
we must have sinned
you must have sinned
they must have sinned	I must have been sinning
you must have been sinning
she must have been sinning
we must have been sinning
you must have been sinning
they must have been sinning	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't sin
you mustn't sin
she mustn't sin
we mustn't sin
you mustn't sin
they mustn't sin 	I mustn't be sinning
you mustn't be sinning
she mustn't be sinning
we mustn't be sinning
you mustn't be sinning
they mustn't be sinning	I mustn't have sinned
you mustn't have sinned
she mustn't have sinned
we mustn't have sinned
you mustn't have sinned
they mustn't have sinned	I mustn't have been sinning
you mustn't have been sinning
she mustn't have been sinning
we mustn't have been sinning
you mustn't have been sinning
they mustn't have been sinning	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I sin?
must you sin?
must she sin?
must we sin?
must you sin?
must they sin? 	must I be sinning?
must you be sinning?
must she be sinning?
must we be sinning?
must you be sinning?
must they be sinning? 	must I have sinned?
must you have sinned?
must she have sinned?
must we have sinned?
must you have sinned?
must they have sinned? 	must I have been sinning?
must you have been sinning?
must she have been sinning?
must we have been sinning?
must you have been sinning?
must they have been sinning? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I sin?
mustn't you sin?
mustn't she sin?
mustn't we sin?
mustn't you sin?
mustn't they sin? 	mustn't I be sinning?
mustn't you be sinning?
mustn't she be sinning?
mustn't we be sinning?
mustn't you be sinning?
mustn't they be sinning? 	mustn't I have sinned?
mustn't you have sinned?
mustn't she have sinned?
mustn't we have sinned?
mustn't you have sinned?
mustn't they have sinned? 	mustn't I have been sinning?
mustn't you have been sinning?
mustn't she have been sinning?
mustn't we have been sinning?
mustn't you have been sinning?
mustn't they have been sinning?