I could advocate you could advocate he could advocate we could advocate you could advocate they could advocate
V-ing form
I could be advocating you could be advocating he could be advocating we could be advocating you could be advocating they could be advocating
Perfect
I could have advocated you could have advocated he could have advocated we could have advocated you could have advocated they could have advocated
V-ing perfect
I could have been advocating you could have been advocating he could have been advocating we could have been advocating you could have been advocating they could have been advocating
Negation
Simple form
I couldn't advocate you couldn't advocate he couldn't advocate we couldn't advocate you couldn't advocate they couldn't advocate
V-ing form
I couldn't be advocating you couldn't be advocating he couldn't be advocating we couldn't be advocating you couldn't be advocating they couldn't be advocating
Perfect
I couldn't have advocated you couldn't have advocated he couldn't have advocated we couldn't have advocated you couldn't have advocated they couldn't have advocated
V-ing perfect
I couldn't have been advocating you couldn't have been advocating he couldn't have been advocating we couldn't have been advocating you couldn't have been advocating they couldn't have been advocating
Interrogative form
Simple form
could I advocate? could you advocate? could he advocate? could we advocate? could you advocate? could they advocate?
V-ing form
could I be advocating? could you be advocating? could he be advocating? could we be advocating? could you be advocating? could they be advocating?
Perfect
could I have advocated? could you have advocated? could he have advocated? could we have advocated? could you have advocated? could they have advocated?
V-ing perfect
could I have been advocating? could you have been advocating? could he have been advocating? could we have been advocating? could you have been advocating? could they have been advocating?
Interro-negative form
Simple form
couldn't I advocate? couldn't you advocate? couldn't he advocate? couldn't we advocate? couldn't you advocate? couldn't they advocate?
V-ing form
couldn't I be advocating? couldn't you be advocating? couldn't he be advocating? couldn't we be advocating? couldn't you be advocating? couldn't they be advocating?
Perfect
couldn't I have advocated? couldn't you have advocated? couldn't he have advocated? couldn't we have advocated? couldn't you have advocated? couldn't they have advocated?
V-ing perfect
couldn't I have been advocating? couldn't you have been advocating? couldn't he have been advocating? couldn't we have been advocating? couldn't you have been advocating? couldn't they have been advocating?