could straighten
Verbo regular: straighten - straightened- straightened

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could straighten
you could straighten
he could straighten
we could straighten
you could straighten
they could straighten 	I could be straightening
you could be straightening
he could be straightening
we could be straightening
you could be straightening
they could be straightening	I could have straightened
you could have straightened
he could have straightened
we could have straightened
you could have straightened
they could have straightened	I could have been straightening
you could have been straightening
he could have been straightening
we could have been straightening
you could have been straightening
they could have been straightening	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I couldn't straighten
you couldn't straighten
he couldn't straighten
we couldn't straighten
you couldn't straighten
they couldn't straighten 	I couldn't be straightening
you couldn't be straightening
he couldn't be straightening
we couldn't be straightening
you couldn't be straightening
they couldn't be straightening	I couldn't have straightened
you couldn't have straightened
he couldn't have straightened
we couldn't have straightened
you couldn't have straightened
they couldn't have straightened	I couldn't have been straightening
you couldn't have been straightening
he couldn't have been straightening
we couldn't have been straightening
you couldn't have been straightening
they couldn't have been straightening	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I straighten?
could you straighten?
could he straighten?
could we straighten?
could you straighten?
could they straighten? 	could I be straightening?
could you be straightening?
could he be straightening?
could we be straightening?
could you be straightening?
could they be straightening? 	could I have straightened?
could you have straightened?
could he have straightened?
could we have straightened?
could you have straightened?
could they have straightened? 	could I have been straightening?
could you have been straightening?
could he have been straightening?
could we have been straightening?
could you have been straightening?
could they have been straightening? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
couldn't I straighten?
couldn't you straighten?
couldn't he straighten?
couldn't we straighten?
couldn't you straighten?
couldn't they straighten? 	couldn't I be straightening?
couldn't you be straightening?
couldn't he be straightening?
couldn't we be straightening?
couldn't you be straightening?
couldn't they be straightening? 	couldn't I have straightened?
couldn't you have straightened?
couldn't he have straightened?
couldn't we have straightened?
couldn't you have straightened?
couldn't they have straightened? 	couldn't I have been straightening?
couldn't you have been straightening?
couldn't he have been straightening?
couldn't we have been straightening?
couldn't you have been straightening?
couldn't they have been straightening?