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