could caution
Verbo regular: caution - cautioned- cautioned

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could caution
you could caution
he could caution
we could caution
you could caution
they could caution 	I could be cautioning
you could be cautioning
he could be cautioning
we could be cautioning
you could be cautioning
they could be cautioning	I could have cautioned
you could have cautioned
he could have cautioned
we could have cautioned
you could have cautioned
they could have cautioned	I could have been cautioning
you could have been cautioning
he could have been cautioning
we could have been cautioning
you could have been cautioning
they could have been cautioning	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I couldn't caution
you couldn't caution
he couldn't caution
we couldn't caution
you couldn't caution
they couldn't caution 	I couldn't be cautioning
you couldn't be cautioning
he couldn't be cautioning
we couldn't be cautioning
you couldn't be cautioning
they couldn't be cautioning	I couldn't have cautioned
you couldn't have cautioned
he couldn't have cautioned
we couldn't have cautioned
you couldn't have cautioned
they couldn't have cautioned	I couldn't have been cautioning
you couldn't have been cautioning
he couldn't have been cautioning
we couldn't have been cautioning
you couldn't have been cautioning
they couldn't have been cautioning	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I caution?
could you caution?
could he caution?
could we caution?
could you caution?
could they caution? 	could I be cautioning?
could you be cautioning?
could he be cautioning?
could we be cautioning?
could you be cautioning?
could they be cautioning? 	could I have cautioned?
could you have cautioned?
could he have cautioned?
could we have cautioned?
could you have cautioned?
could they have cautioned? 	could I have been cautioning?
could you have been cautioning?
could he have been cautioning?
could we have been cautioning?
could you have been cautioning?
could they have been cautioning? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
couldn't I caution?
couldn't you caution?
couldn't he caution?
couldn't we caution?
couldn't you caution?
couldn't they caution? 	couldn't I be cautioning?
couldn't you be cautioning?
couldn't he be cautioning?
couldn't we be cautioning?
couldn't you be cautioning?
couldn't they be cautioning? 	couldn't I have cautioned?
couldn't you have cautioned?
couldn't he have cautioned?
couldn't we have cautioned?
couldn't you have cautioned?
couldn't they have cautioned? 	couldn't I have been cautioning?
couldn't you have been cautioning?
couldn't he have been cautioning?
couldn't we have been cautioning?
couldn't you have been cautioning?
couldn't they have been cautioning?