could upturn
Verbo regular: upturn - upturned- upturned

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could upturn
you could upturn
he could upturn
we could upturn
you could upturn
they could upturn 	I could be upturning
you could be upturning
he could be upturning
we could be upturning
you could be upturning
they could be upturning	I could have upturned
you could have upturned
he could have upturned
we could have upturned
you could have upturned
they could have upturned	I could have been upturning
you could have been upturning
he could have been upturning
we could have been upturning
you could have been upturning
they could have been upturning	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could not upturn
you could not upturn
he could not upturn
we could not upturn
you could not upturn
they could not upturn 	I could not be upturning
you could not be upturning
he could not be upturning
we could not be upturning
you could not be upturning
they could not be upturning	I could not have upturned
you could not have upturned
he could not have upturned
we could not have upturned
you could not have upturned
they could not have upturned	I could not have been upturning
you could not have been upturning
he could not have been upturning
we could not have been upturning
you could not have been upturning
they could not have been upturning	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I upturn?
could you upturn?
could he upturn?
could we upturn?
could you upturn?
could they upturn? 	could I be upturning?
could you be upturning?
could he be upturning?
could we be upturning?
could you be upturning?
could they be upturning? 	could I have upturned?
could you have upturned?
could he have upturned?
could we have upturned?
could you have upturned?
could they have upturned? 	could I have been upturning?
could you have been upturning?
could he have been upturning?
could we have been upturning?
could you have been upturning?
could they have been upturning? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I not upturn?
could you not upturn?
could he not upturn?
could we not upturn?
could you not upturn?
could they not upturn? 	could I not be upturning?
could you not be upturning?
could he not be upturning?
could we not be upturning?
could you not be upturning?
could they not be upturning? 	could I not have upturned?
could you not have upturned?
could he not have upturned?
could we not have upturned?
could you not have upturned?
could they not have upturned? 	could I not have been upturning?
could you not have been upturning?
could he not have been upturning?
could we not have been upturning?
could you not have been upturning?
could they not have been upturning?