could tunnel
Verbo regular: tunnel - tunnelled- tunnelled

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could tunnel
you could tunnel
he could tunnel
we could tunnel
you could tunnel
they could tunnel 	I could be tunnelling
you could be tunnelling
he could be tunnelling
we could be tunnelling
you could be tunnelling
they could be tunnelling	I could have tunnelled
you could have tunnelled
he could have tunnelled
we could have tunnelled
you could have tunnelled
they could have tunnelled	I could have been tunnelling
you could have been tunnelling
he could have been tunnelling
we could have been tunnelling
you could have been tunnelling
they could have been tunnelling	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could not tunnel
you could not tunnel
he could not tunnel
we could not tunnel
you could not tunnel
they could not tunnel 	I could not be tunnelling
you could not be tunnelling
he could not be tunnelling
we could not be tunnelling
you could not be tunnelling
they could not be tunnelling	I could not have tunnelled
you could not have tunnelled
he could not have tunnelled
we could not have tunnelled
you could not have tunnelled
they could not have tunnelled	I could not have been tunnelling
you could not have been tunnelling
he could not have been tunnelling
we could not have been tunnelling
you could not have been tunnelling
they could not have been tunnelling	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I tunnel?
could you tunnel?
could he tunnel?
could we tunnel?
could you tunnel?
could they tunnel? 	could I be tunnelling?
could you be tunnelling?
could he be tunnelling?
could we be tunnelling?
could you be tunnelling?
could they be tunnelling? 	could I have tunnelled?
could you have tunnelled?
could he have tunnelled?
could we have tunnelled?
could you have tunnelled?
could they have tunnelled? 	could I have been tunnelling?
could you have been tunnelling?
could he have been tunnelling?
could we have been tunnelling?
could you have been tunnelling?
could they have been tunnelling? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I not tunnel?
could you not tunnel?
could he not tunnel?
could we not tunnel?
could you not tunnel?
could they not tunnel? 	could I not be tunnelling?
could you not be tunnelling?
could he not be tunnelling?
could we not be tunnelling?
could you not be tunnelling?
could they not be tunnelling? 	could I not have tunnelled?
could you not have tunnelled?
could he not have tunnelled?
could we not have tunnelled?
could you not have tunnelled?
could they not have tunnelled? 	could I not have been tunnelling?
could you not have been tunnelling?
could he not have been tunnelling?
could we not have been tunnelling?
could you not have been tunnelling?
could they not have been tunnelling?