can riff
Verbo regular: riff - riffed- riffed

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I can riff
you can riff
he can riff
we can riff
you can riff
they can riff 	I can be riffing
you can be riffing
he can be riffing
we can be riffing
you can be riffing
they can be riffing	I can have riffed
you can have riffed
he can have riffed
we can have riffed
you can have riffed
they can have riffed	I can have been riffing
you can have been riffing
he can have been riffing
we can have been riffing
you can have been riffing
they can have been riffing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I cannot riff
you cannot riff
he cannot riff
we cannot riff
you cannot riff
they cannot riff 	I cannot be riffing
you cannot be riffing
he cannot be riffing
we cannot be riffing
you cannot be riffing
they cannot be riffing	I cannot have riffed
you cannot have riffed
he cannot have riffed
we cannot have riffed
you cannot have riffed
they cannot have riffed	I cannot have been riffing
you cannot have been riffing
he cannot have been riffing
we cannot have been riffing
you cannot have been riffing
they cannot have been riffing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
can I riff?
can you riff?
can he riff?
can we riff?
can you riff?
can they riff? 	can I be riffing?
can you be riffing?
can he be riffing?
can we be riffing?
can you be riffing?
can they be riffing? 	can I have riffed?
can you have riffed?
can he have riffed?
can we have riffed?
can you have riffed?
can they have riffed? 	can I have been riffing?
can you have been riffing?
can he have been riffing?
can we have been riffing?
can you have been riffing?
can they have been riffing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
can I not riff?
can you not riff?
can he not riff?
can we not riff?
can you not riff?
can they not riff? 	can I not be riffing?
can you not be riffing?
can he not be riffing?
can we not be riffing?
can you not be riffing?
can they not be riffing? 	can I not have riffed?
can you not have riffed?
can he not have riffed?
can we not have riffed?
can you not have riffed?
can they not have riffed? 	can I not have been riffing?
can you not have been riffing?
can he not have been riffing?
can we not have been riffing?
can you not have been riffing?
can they not have been riffing?