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