English verb conjugation
COULD RETIGHTEN

Regular verb: retighten - retightened - retightened

Affirmation

Simple form	V-ing form
I could retighten you could retighten he could retighten we could retighten you could retighten they could retighten	I could be retightening you could be retightening he could be retightening we could be retightening you could be retightening they could be retightening
Perfect	V-ing perfect
I could have retightened you could have retightened he could have retightened we could have retightened you could have retightened they could have retightened	I could have been retightening you could have been retightening he could have been retightening we could have been retightening you could have been retightening they could have been retightening

Negation

Simple form	V-ing form
I couldn't retighten you couldn't retighten he couldn't retighten we couldn't retighten you couldn't retighten they couldn't retighten	I couldn't be retightening you couldn't be retightening he couldn't be retightening we couldn't be retightening you couldn't be retightening they couldn't be retightening
Perfect	V-ing perfect
I couldn't have retightened you couldn't have retightened he couldn't have retightened we couldn't have retightened you couldn't have retightened they couldn't have retightened	I couldn't have been retightening you couldn't have been retightening he couldn't have been retightening we couldn't have been retightening you couldn't have been retightening they couldn't have been retightening

Interrogative form

Simple form	V-ing form
could I retighten? could you retighten? could he retighten? could we retighten? could you retighten? could they retighten?	could I be retightening? could you be retightening? could he be retightening? could we be retightening? could you be retightening? could they be retightening?
Perfect	V-ing perfect
could I have retightened? could you have retightened? could he have retightened? could we have retightened? could you have retightened? could they have retightened?	could I have been retightening? could you have been retightening? could he have been retightening? could we have been retightening? could you have been retightening? could they have been retightening?

Interro-negative form

Simple form	V-ing form
couldn't I retighten? couldn't you retighten? couldn't he retighten? couldn't we retighten? couldn't you retighten? couldn't they retighten?	couldn't I be retightening? couldn't you be retightening? couldn't he be retightening? couldn't we be retightening? couldn't you be retightening? couldn't they be retightening?
Perfect	V-ing perfect
couldn't I have retightened? couldn't you have retightened? couldn't he have retightened? couldn't we have retightened? couldn't you have retightened? couldn't they have retightened?	couldn't I have been retightening? couldn't you have been retightening? couldn't he have been retightening? couldn't we have been retightening? couldn't you have been retightening? couldn't they have been retightening?