could riff
Verbe régulier : riff - riffed- riffed

Affirmation 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
I could riff
you could riff
he could riff
we could riff
you could riff
they could riff 	I could be riffing
you could be riffing
he could be riffing
we could be riffing
you could be riffing
they could be riffing	I could have riffed
you could have riffed
he could have riffed
we could have riffed
you could have riffed
they could have riffed	I could have been riffing
you could have been riffing
he could have been riffing
we could have been riffing
you could have been riffing
they could have been riffing	

Négation 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
I couldn't riff
you couldn't riff
he couldn't riff
we couldn't riff
you couldn't riff
they couldn't riff 	I couldn't be riffing
you couldn't be riffing
he couldn't be riffing
we couldn't be riffing
you couldn't be riffing
they couldn't be riffing	I couldn't have riffed
you couldn't have riffed
he couldn't have riffed
we couldn't have riffed
you couldn't have riffed
they couldn't have riffed	I couldn't have been riffing
you couldn't have been riffing
he couldn't have been riffing
we couldn't have been riffing
you couldn't have been riffing
they couldn't have been riffing	

Forme interrogative 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
could I riff?
could you riff?
could he riff?
could we riff?
could you riff?
could they riff? 	could I be riffing?
could you be riffing?
could he be riffing?
could we be riffing?
could you be riffing?
could they be riffing? 	could I have riffed?
could you have riffed?
could he have riffed?
could we have riffed?
could you have riffed?
could they have riffed? 	could I have been riffing?
could you have been riffing?
could he have been riffing?
could we have been riffing?
could you have been riffing?
could they have been riffing? 	

Forme interro-négative 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
couldn't I riff?
couldn't you riff?
couldn't he riff?
couldn't we riff?
couldn't you riff?
couldn't they riff? 	couldn't I be riffing?
couldn't you be riffing?
couldn't he be riffing?
couldn't we be riffing?
couldn't you be riffing?
couldn't they be riffing? 	couldn't I have riffed?
couldn't you have riffed?
couldn't he have riffed?
couldn't we have riffed?
couldn't you have riffed?
couldn't they have riffed? 	couldn't I have been riffing?
couldn't you have been riffing?
couldn't he have been riffing?
couldn't we have been riffing?
couldn't you have been riffing?
couldn't they have been riffing?