English verb conjugation
COULD TUNNEL

Regular verb: tunnel - tunnelled - tunnelled

Affirmation

Simple form	V-ing form
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
Perfect	V-ing perfect
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

Negation

Simple form	V-ing form
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
Perfect	V-ing perfect
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

Interrogative form

Simple form	V-ing form
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?
Perfect	V-ing perfect
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?

Interro-negative form

Simple form	V-ing form
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?
Perfect	V-ing perfect
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?