English verb conjugation
COULD DOUBLE

Regular verb: double - doubled - doubled

Affirmation

Simple form	V-ing form
I could double you could double he could double we could double you could double they could double	I could be doubling you could be doubling he could be doubling we could be doubling you could be doubling they could be doubling
Perfect	V-ing perfect
I could have doubled you could have doubled he could have doubled we could have doubled you could have doubled they could have doubled	I could have been doubling you could have been doubling he could have been doubling we could have been doubling you could have been doubling they could have been doubling

Negation

Simple form	V-ing form
I couldn't double you couldn't double he couldn't double we couldn't double you couldn't double they couldn't double	I couldn't be doubling you couldn't be doubling he couldn't be doubling we couldn't be doubling you couldn't be doubling they couldn't be doubling
Perfect	V-ing perfect
I couldn't have doubled you couldn't have doubled he couldn't have doubled we couldn't have doubled you couldn't have doubled they couldn't have doubled	I couldn't have been doubling you couldn't have been doubling he couldn't have been doubling we couldn't have been doubling you couldn't have been doubling they couldn't have been doubling

Interrogative form

Simple form	V-ing form
could I double? could you double? could he double? could we double? could you double? could they double?	could I be doubling? could you be doubling? could he be doubling? could we be doubling? could you be doubling? could they be doubling?
Perfect	V-ing perfect
could I have doubled? could you have doubled? could he have doubled? could we have doubled? could you have doubled? could they have doubled?	could I have been doubling? could you have been doubling? could he have been doubling? could we have been doubling? could you have been doubling? could they have been doubling?

Interro-negative form

Simple form	V-ing form
couldn't I double? couldn't you double? couldn't he double? couldn't we double? couldn't you double? couldn't they double?	couldn't I be doubling? couldn't you be doubling? couldn't he be doubling? couldn't we be doubling? couldn't you be doubling? couldn't they be doubling?
Perfect	V-ing perfect
couldn't I have doubled? couldn't you have doubled? couldn't he have doubled? couldn't we have doubled? couldn't you have doubled? couldn't they have doubled?	couldn't I have been doubling? couldn't you have been doubling? couldn't he have been doubling? couldn't we have been doubling? couldn't you have been doubling? couldn't they have been doubling?