I could brainstorm you could brainstorm she could brainstorm we could brainstorm you could brainstorm they could brainstorm
V-ing form
I could be brainstorming you could be brainstorming she could be brainstorming we could be brainstorming you could be brainstorming they could be brainstorming
Perfect
I could have brainstormed you could have brainstormed she could have brainstormed we could have brainstormed you could have brainstormed they could have brainstormed
V-ing perfect
I could have been brainstorming you could have been brainstorming she could have been brainstorming we could have been brainstorming you could have been brainstorming they could have been brainstorming
Negation
Simple form
I couldn't brainstorm you couldn't brainstorm she couldn't brainstorm we couldn't brainstorm you couldn't brainstorm they couldn't brainstorm
V-ing form
I couldn't be brainstorming you couldn't be brainstorming she couldn't be brainstorming we couldn't be brainstorming you couldn't be brainstorming they couldn't be brainstorming
Perfect
I couldn't have brainstormed you couldn't have brainstormed she couldn't have brainstormed we couldn't have brainstormed you couldn't have brainstormed they couldn't have brainstormed
V-ing perfect
I couldn't have been brainstorming you couldn't have been brainstorming she couldn't have been brainstorming we couldn't have been brainstorming you couldn't have been brainstorming they couldn't have been brainstorming
Interrogative form
Simple form
could I brainstorm? could you brainstorm? could she brainstorm? could we brainstorm? could you brainstorm? could they brainstorm?
V-ing form
could I be brainstorming? could you be brainstorming? could she be brainstorming? could we be brainstorming? could you be brainstorming? could they be brainstorming?
Perfect
could I have brainstormed? could you have brainstormed? could she have brainstormed? could we have brainstormed? could you have brainstormed? could they have brainstormed?
V-ing perfect
could I have been brainstorming? could you have been brainstorming? could she have been brainstorming? could we have been brainstorming? could you have been brainstorming? could they have been brainstorming?
Interro-negative form
Simple form
couldn't I brainstorm? couldn't you brainstorm? couldn't she brainstorm? couldn't we brainstorm? couldn't you brainstorm? couldn't they brainstorm?
V-ing form
couldn't I be brainstorming? couldn't you be brainstorming? couldn't she be brainstorming? couldn't we be brainstorming? couldn't you be brainstorming? couldn't they be brainstorming?
Perfect
couldn't I have brainstormed? couldn't you have brainstormed? couldn't she have brainstormed? couldn't we have brainstormed? couldn't you have brainstormed? couldn't they have brainstormed?
V-ing perfect
couldn't I have been brainstorming? couldn't you have been brainstorming? couldn't she have been brainstorming? couldn't we have been brainstorming? couldn't you have been brainstorming? couldn't they have been brainstorming?