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 couldn't tiff
you couldn't tiff
he couldn't tiff
we couldn't tiff
you couldn't tiff
they couldn't tiff 	I couldn't be tiffing
you couldn't be tiffing
he couldn't be tiffing
we couldn't be tiffing
you couldn't be tiffing
they couldn't be tiffing	I couldn't have tiffed
you couldn't have tiffed
he couldn't have tiffed
we couldn't have tiffed
you couldn't have tiffed
they couldn't have tiffed	I couldn't have been tiffing
you couldn't have been tiffing
he couldn't have been tiffing
we couldn't have been tiffing
you couldn't have been tiffing
they couldn't 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 	
couldn't I tiff?
couldn't you tiff?
couldn't he tiff?
couldn't we tiff?
couldn't you tiff?
couldn't they tiff? 	couldn't I be tiffing?
couldn't you be tiffing?
couldn't he be tiffing?
couldn't we be tiffing?
couldn't you be tiffing?
couldn't they be tiffing? 	couldn't I have tiffed?
couldn't you have tiffed?
couldn't he have tiffed?
couldn't we have tiffed?
couldn't you have tiffed?
couldn't they have tiffed? 	couldn't I have been tiffing?
couldn't you have been tiffing?
couldn't he have been tiffing?
couldn't we have been tiffing?
couldn't you have been tiffing?
couldn't they have been tiffing?