English verb conjugation
COULD USE

Regular verb: use - used - used

Affirmation

Simple form	V-ing form
I could use you could use he could use we could use you could use they could use	I could be using you could be using he could be using we could be using you could be using they could be using
Perfect	V-ing perfect
I could have used you could have used he could have used we could have used you could have used they could have used	I could have been using you could have been using he could have been using we could have been using you could have been using they could have been using

Negation

Simple form	V-ing form
I couldn't use you couldn't use he couldn't use we couldn't use you couldn't use they couldn't use	I couldn't be using you couldn't be using he couldn't be using we couldn't be using you couldn't be using they couldn't be using
Perfect	V-ing perfect
I couldn't have used you couldn't have used he couldn't have used we couldn't have used you couldn't have used they couldn't have used	I couldn't have been using you couldn't have been using he couldn't have been using we couldn't have been using you couldn't have been using they couldn't have been using

Interrogative form

Simple form	V-ing form
could I use? could you use? could he use? could we use? could you use? could they use?	could I be using? could you be using? could he be using? could we be using? could you be using? could they be using?
Perfect	V-ing perfect
could I have used? could you have used? could he have used? could we have used? could you have used? could they have used?	could I have been using? could you have been using? could he have been using? could we have been using? could you have been using? could they have been using?

Interro-negative form

Simple form	V-ing form
couldn't I use? couldn't you use? couldn't he use? couldn't we use? couldn't you use? couldn't they use?	couldn't I be using? couldn't you be using? couldn't he be using? couldn't we be using? couldn't you be using? couldn't they be using?
Perfect	V-ing perfect
couldn't I have used? couldn't you have used? couldn't he have used? couldn't we have used? couldn't you have used? couldn't they have used?	couldn't I have been using? couldn't you have been using? couldn't he have been using? couldn't we have been using? couldn't you have been using? couldn't they have been using?