I could rank you could rank he could rank we could rank you could rank they could rank
V-ing form
I could be ranking you could be ranking he could be ranking we could be ranking you could be ranking they could be ranking
Perfect
I could have ranked you could have ranked he could have ranked we could have ranked you could have ranked they could have ranked
V-ing perfect
I could have been ranking you could have been ranking he could have been ranking we could have been ranking you could have been ranking they could have been ranking
Negation
Simple form
I could not rank you could not rank he could not rank we could not rank you could not rank they could not rank
V-ing form
I could not be ranking you could not be ranking he could not be ranking we could not be ranking you could not be ranking they could not be ranking
Perfect
I could not have ranked you could not have ranked he could not have ranked we could not have ranked you could not have ranked they could not have ranked
V-ing perfect
I could not have been ranking you could not have been ranking he could not have been ranking we could not have been ranking you could not have been ranking they could not have been ranking
Interrogative form
Simple form
could I rank? could you rank? could he rank? could we rank? could you rank? could they rank?
V-ing form
could I be ranking? could you be ranking? could he be ranking? could we be ranking? could you be ranking? could they be ranking?
Perfect
could I have ranked? could you have ranked? could he have ranked? could we have ranked? could you have ranked? could they have ranked?
V-ing perfect
could I have been ranking? could you have been ranking? could he have been ranking? could we have been ranking? could you have been ranking? could they have been ranking?
Interro-negative form
Simple form
could I not rank? could you not rank? could he not rank? could we not rank? could you not rank? could they not rank?
V-ing form
could I not be ranking? could you not be ranking? could he not be ranking? could we not be ranking? could you not be ranking? could they not be ranking?
Perfect
could I not have ranked? could you not have ranked? could he not have ranked? could we not have ranked? could you not have ranked? could they not have ranked?
V-ing perfect
could I not have been ranking? could you not have been ranking? could he not have been ranking? could we not have been ranking? could you not have been ranking? could they not have been ranking?