English verb conjugation
COULD GAIN

Regular verb: gain - gained - gained

Affirmation

Simple form	V-ing form
I could gain you could gain he could gain we could gain you could gain they could gain	I could be gaining you could be gaining he could be gaining we could be gaining you could be gaining they could be gaining
Perfect	V-ing perfect
I could have gained you could have gained he could have gained we could have gained you could have gained they could have gained	I could have been gaining you could have been gaining he could have been gaining we could have been gaining you could have been gaining they could have been gaining

Negation

Simple form	V-ing form
I couldn't gain you couldn't gain he couldn't gain we couldn't gain you couldn't gain they couldn't gain	I couldn't be gaining you couldn't be gaining he couldn't be gaining we couldn't be gaining you couldn't be gaining they couldn't be gaining
Perfect	V-ing perfect
I couldn't have gained you couldn't have gained he couldn't have gained we couldn't have gained you couldn't have gained they couldn't have gained	I couldn't have been gaining you couldn't have been gaining he couldn't have been gaining we couldn't have been gaining you couldn't have been gaining they couldn't have been gaining

Interrogative form

Simple form	V-ing form
could I gain? could you gain? could he gain? could we gain? could you gain? could they gain?	could I be gaining? could you be gaining? could he be gaining? could we be gaining? could you be gaining? could they be gaining?
Perfect	V-ing perfect
could I have gained? could you have gained? could he have gained? could we have gained? could you have gained? could they have gained?	could I have been gaining? could you have been gaining? could he have been gaining? could we have been gaining? could you have been gaining? could they have been gaining?

Interro-negative form

Simple form	V-ing form
couldn't I gain? couldn't you gain? couldn't he gain? couldn't we gain? couldn't you gain? couldn't they gain?	couldn't I be gaining? couldn't you be gaining? couldn't he be gaining? couldn't we be gaining? couldn't you be gaining? couldn't they be gaining?
Perfect	V-ing perfect
couldn't I have gained? couldn't you have gained? couldn't he have gained? couldn't we have gained? couldn't you have gained? couldn't they have gained?	couldn't I have been gaining? couldn't you have been gaining? couldn't he have been gaining? couldn't we have been gaining? couldn't you have been gaining? couldn't they have been gaining?