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 must not sour
you must not sour
she must not sour
we must not sour
you must not sour
they must not sour 	I must not be souring
you must not be souring
she must not be souring
we must not be souring
you must not be souring
they must not be souring	I must not have soured
you must not have soured
she must not have soured
we must not have soured
you must not have soured
they must not have soured	I must not have been souring
you must not have been souring
she must not have been souring
we must not have been souring
you must not have been souring
they must not 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 	
must I not sour?
must you not sour?
must she not sour?
must we not sour?
must you not sour?
must they not sour? 	must I not be souring?
must you not be souring?
must she not be souring?
must we not be souring?
must you not be souring?
must they not be souring? 	must I not have soured?
must you not have soured?
must she not have soured?
must we not have soured?
must you not have soured?
must they not have soured? 	must I not have been souring?
must you not have been souring?
must she not have been souring?
must we not have been souring?
must you not have been souring?
must they not have been souring?