could heighten
Verbo regular: heighten - heightened- heightened

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could heighten
you could heighten
he could heighten
we could heighten
you could heighten
they could heighten 	I could be heightening
you could be heightening
he could be heightening
we could be heightening
you could be heightening
they could be heightening	I could have heightened
you could have heightened
he could have heightened
we could have heightened
you could have heightened
they could have heightened	I could have been heightening
you could have been heightening
he could have been heightening
we could have been heightening
you could have been heightening
they could have been heightening	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I couldn't heighten
you couldn't heighten
he couldn't heighten
we couldn't heighten
you couldn't heighten
they couldn't heighten 	I couldn't be heightening
you couldn't be heightening
he couldn't be heightening
we couldn't be heightening
you couldn't be heightening
they couldn't be heightening	I couldn't have heightened
you couldn't have heightened
he couldn't have heightened
we couldn't have heightened
you couldn't have heightened
they couldn't have heightened	I couldn't have been heightening
you couldn't have been heightening
he couldn't have been heightening
we couldn't have been heightening
you couldn't have been heightening
they couldn't have been heightening	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I heighten?
could you heighten?
could he heighten?
could we heighten?
could you heighten?
could they heighten? 	could I be heightening?
could you be heightening?
could he be heightening?
could we be heightening?
could you be heightening?
could they be heightening? 	could I have heightened?
could you have heightened?
could he have heightened?
could we have heightened?
could you have heightened?
could they have heightened? 	could I have been heightening?
could you have been heightening?
could he have been heightening?
could we have been heightening?
could you have been heightening?
could they have been heightening? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
couldn't I heighten?
couldn't you heighten?
couldn't he heighten?
couldn't we heighten?
couldn't you heighten?
couldn't they heighten? 	couldn't I be heightening?
couldn't you be heightening?
couldn't he be heightening?
couldn't we be heightening?
couldn't you be heightening?
couldn't they be heightening? 	couldn't I have heightened?
couldn't you have heightened?
couldn't he have heightened?
couldn't we have heightened?
couldn't you have heightened?
couldn't they have heightened? 	couldn't I have been heightening?
couldn't you have been heightening?
couldn't he have been heightening?
couldn't we have been heightening?
couldn't you have been heightening?
couldn't they have been heightening?