could tiff
Verbe régulier : tiff - tiffed- tiffed

Affirmation 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
I could tiff
you could tiff
he could tiff
we could tiff
you could tiff
they could tiff 	I could be tiffing
you could be tiffing
he could be tiffing
we could be tiffing
you could be tiffing
they could be tiffing	I could have tiffed
you could have tiffed
he could have tiffed
we could have tiffed
you could have tiffed
they could have tiffed	I could have been tiffing
you could have been tiffing
he could have been tiffing
we could have been tiffing
you could have been tiffing
they could have been tiffing	

Négation 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
I could not tiff
you could not tiff
he could not tiff
we could not tiff
you could not tiff
they could not tiff 	I could not be tiffing
you could not be tiffing
he could not be tiffing
we could not be tiffing
you could not be tiffing
they could not be tiffing	I could not have tiffed
you could not have tiffed
he could not have tiffed
we could not have tiffed
you could not have tiffed
they could not have tiffed	I could not have been tiffing
you could not have been tiffing
he could not have been tiffing
we could not have been tiffing
you could not have been tiffing
they could not have been tiffing	

Forme interrogative 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
could I tiff?
could you tiff?
could he tiff?
could we tiff?
could you tiff?
could they tiff? 	could I be tiffing?
could you be tiffing?
could he be tiffing?
could we be tiffing?
could you be tiffing?
could they be tiffing? 	could I have tiffed?
could you have tiffed?
could he have tiffed?
could we have tiffed?
could you have tiffed?
could they have tiffed? 	could I have been tiffing?
could you have been tiffing?
could he have been tiffing?
could we have been tiffing?
could you have been tiffing?
could they have been tiffing? 	

Forme interro-négative 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
could I not tiff?
could you not tiff?
could he not tiff?
could we not tiff?
could you not tiff?
could they not tiff? 	could I not be tiffing?
could you not be tiffing?
could he not be tiffing?
could we not be tiffing?
could you not be tiffing?
could they not be tiffing? 	could I not have tiffed?
could you not have tiffed?
could he not have tiffed?
could we not have tiffed?
could you not have tiffed?
could they not have tiffed? 	could I not have been tiffing?
could you not have been tiffing?
could he not have been tiffing?
could we not have been tiffing?
could you not have been tiffing?
could they not have been tiffing?