English verb conjugation
COULD USE

Regular verb: use - used - used

Affirmation

Simple form	V-ing form
I could use you could use she could use we could use you could use they could use	I could be using you could be using she 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 she 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 she 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 she 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 she 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 she 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 she 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 she use? could we use? could you use? could they use?	could I be using? could you be using? could she 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 she 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 she 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 she 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 she 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 she 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 she have been using? couldn't we have been using? couldn't you have been using? couldn't they have been using?