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 couldn't tunnel you couldn't tunnel he couldn't tunnel we couldn't tunnel you couldn't tunnel they couldn't tunnel	I couldn't be tunnelling you couldn't be tunnelling he couldn't be tunnelling we couldn't be tunnelling you couldn't be tunnelling they couldn't be tunnelling
Perfect	V-ing perfect
I couldn't have tunnelled you couldn't have tunnelled he couldn't have tunnelled we couldn't have tunnelled you couldn't have tunnelled they couldn't have tunnelled	I couldn't have been tunnelling you couldn't have been tunnelling he couldn't have been tunnelling we couldn't have been tunnelling you couldn't have been tunnelling they couldn't 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
couldn't I tunnel? couldn't you tunnel? couldn't he tunnel? couldn't we tunnel? couldn't you tunnel? couldn't they tunnel?	couldn't I be tunnelling? couldn't you be tunnelling? couldn't he be tunnelling? couldn't we be tunnelling? couldn't you be tunnelling? couldn't they be tunnelling?
Perfect	V-ing perfect
couldn't I have tunnelled? couldn't you have tunnelled? couldn't he have tunnelled? couldn't we have tunnelled? couldn't you have tunnelled? couldn't they have tunnelled?	couldn't I have been tunnelling? couldn't you have been tunnelling? couldn't he have been tunnelling? couldn't we have been tunnelling? couldn't you have been tunnelling? couldn't they have been tunnelling?