must concenter
Verbe régulier : concenter - concentered- concentered

Affirmation 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
I must concenter
you must concenter
she must concenter
we must concenter
you must concenter
they must concenter 	I must be concentering
you must be concentering
she must be concentering
we must be concentering
you must be concentering
they must be concentering	I must have concentered
you must have concentered
she must have concentered
we must have concentered
you must have concentered
they must have concentered	I must have been concentering
you must have been concentering
she must have been concentering
we must have been concentering
you must have been concentering
they must have been concentering	

Négation 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
I mustn't concenter
you mustn't concenter
she mustn't concenter
we mustn't concenter
you mustn't concenter
they mustn't concenter 	I mustn't be concentering
you mustn't be concentering
she mustn't be concentering
we mustn't be concentering
you mustn't be concentering
they mustn't be concentering	I mustn't have concentered
you mustn't have concentered
she mustn't have concentered
we mustn't have concentered
you mustn't have concentered
they mustn't have concentered	I mustn't have been concentering
you mustn't have been concentering
she mustn't have been concentering
we mustn't have been concentering
you mustn't have been concentering
they mustn't have been concentering	

Forme interrogative 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
must I concenter?
must you concenter?
must she concenter?
must we concenter?
must you concenter?
must they concenter? 	must I be concentering?
must you be concentering?
must she be concentering?
must we be concentering?
must you be concentering?
must they be concentering? 	must I have concentered?
must you have concentered?
must she have concentered?
must we have concentered?
must you have concentered?
must they have concentered? 	must I have been concentering?
must you have been concentering?
must she have been concentering?
must we have been concentering?
must you have been concentering?
must they have been concentering? 	

Forme interro-négative 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
mustn't I concenter?
mustn't you concenter?
mustn't she concenter?
mustn't we concenter?
mustn't you concenter?
mustn't they concenter? 	mustn't I be concentering?
mustn't you be concentering?
mustn't she be concentering?
mustn't we be concentering?
mustn't you be concentering?
mustn't they be concentering? 	mustn't I have concentered?
mustn't you have concentered?
mustn't she have concentered?
mustn't we have concentered?
mustn't you have concentered?
mustn't they have concentered? 	mustn't I have been concentering?
mustn't you have been concentering?
mustn't she have been concentering?
mustn't we have been concentering?
mustn't you have been concentering?
mustn't they have been concentering?