must backcross
Verbe régulier : backcross - backcrossed- backcrossed

Affirmation 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
I must backcross
you must backcross
he must backcross
we must backcross
you must backcross
they must backcross 	I must be backcrossing
you must be backcrossing
he must be backcrossing
we must be backcrossing
you must be backcrossing
they must be backcrossing	I must have backcrossed
you must have backcrossed
he must have backcrossed
we must have backcrossed
you must have backcrossed
they must have backcrossed	I must have been backcrossing
you must have been backcrossing
he must have been backcrossing
we must have been backcrossing
you must have been backcrossing
they must have been backcrossing	

Négation 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
I mustn't backcross
you mustn't backcross
he mustn't backcross
we mustn't backcross
you mustn't backcross
they mustn't backcross 	I mustn't be backcrossing
you mustn't be backcrossing
he mustn't be backcrossing
we mustn't be backcrossing
you mustn't be backcrossing
they mustn't be backcrossing	I mustn't have backcrossed
you mustn't have backcrossed
he mustn't have backcrossed
we mustn't have backcrossed
you mustn't have backcrossed
they mustn't have backcrossed	I mustn't have been backcrossing
you mustn't have been backcrossing
he mustn't have been backcrossing
we mustn't have been backcrossing
you mustn't have been backcrossing
they mustn't have been backcrossing	

Forme interrogative 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
must I backcross?
must you backcross?
must he backcross?
must we backcross?
must you backcross?
must they backcross? 	must I be backcrossing?
must you be backcrossing?
must he be backcrossing?
must we be backcrossing?
must you be backcrossing?
must they be backcrossing? 	must I have backcrossed?
must you have backcrossed?
must he have backcrossed?
must we have backcrossed?
must you have backcrossed?
must they have backcrossed? 	must I have been backcrossing?
must you have been backcrossing?
must he have been backcrossing?
must we have been backcrossing?
must you have been backcrossing?
must they have been backcrossing? 	

Forme interro-négative 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
mustn't I backcross?
mustn't you backcross?
mustn't he backcross?
mustn't we backcross?
mustn't you backcross?
mustn't they backcross? 	mustn't I be backcrossing?
mustn't you be backcrossing?
mustn't he be backcrossing?
mustn't we be backcrossing?
mustn't you be backcrossing?
mustn't they be backcrossing? 	mustn't I have backcrossed?
mustn't you have backcrossed?
mustn't he have backcrossed?
mustn't we have backcrossed?
mustn't you have backcrossed?
mustn't they have backcrossed? 	mustn't I have been backcrossing?
mustn't you have been backcrossing?
mustn't he have been backcrossing?
mustn't we have been backcrossing?
mustn't you have been backcrossing?
mustn't they have been backcrossing?