must sour
Verbe régulier : sour - soured- soured
Traduction française : surir - aigrir 

Affirmation 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
I must sour
you must sour
she must sour
we must sour
you must sour
they must sour 	I must be souring
you must be souring
she must be souring
we must be souring
you must be souring
they must be souring	I must have soured
you must have soured
she must have soured
we must have soured
you must have soured
they must have soured	I must have been souring
you must have been souring
she must have been souring
we must have been souring
you must have been souring
they must have been souring	

Négation 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
I mustn't sour
you mustn't sour
she mustn't sour
we mustn't sour
you mustn't sour
they mustn't sour 	I mustn't be souring
you mustn't be souring
she mustn't be souring
we mustn't be souring
you mustn't be souring
they mustn't be souring	I mustn't have soured
you mustn't have soured
she mustn't have soured
we mustn't have soured
you mustn't have soured
they mustn't have soured	I mustn't have been souring
you mustn't have been souring
she mustn't have been souring
we mustn't have been souring
you mustn't have been souring
they mustn't have been souring	

Forme interrogative 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
must I sour?
must you sour?
must she sour?
must we sour?
must you sour?
must they sour? 	must I be souring?
must you be souring?
must she be souring?
must we be souring?
must you be souring?
must they be souring? 	must I have soured?
must you have soured?
must she have soured?
must we have soured?
must you have soured?
must they have soured? 	must I have been souring?
must you have been souring?
must she have been souring?
must we have been souring?
must you have been souring?
must they have been souring? 	

Forme interro-négative 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
mustn't I sour?
mustn't you sour?
mustn't she sour?
mustn't we sour?
mustn't you sour?
mustn't they sour? 	mustn't I be souring?
mustn't you be souring?
mustn't she be souring?
mustn't we be souring?
mustn't you be souring?
mustn't they be souring? 	mustn't I have soured?
mustn't you have soured?
mustn't she have soured?
mustn't we have soured?
mustn't you have soured?
mustn't they have soured? 	mustn't I have been souring?
mustn't you have been souring?
mustn't she have been souring?
mustn't we have been souring?
mustn't you have been souring?
mustn't they have been souring?