I could drink you could drink he could drink we could drink you could drink they could drink
V-ing form
I could be drinking you could be drinking he could be drinking we could be drinking you could be drinking they could be drinking
Perfect
I could have drunk you could have drunk he could have drunk we could have drunk you could have drunk they could have drunk
V-ing perfect
I could have been drinking you could have been drinking he could have been drinking we could have been drinking you could have been drinking they could have been drinking
Negation
Simple form
I could not drink you could not drink he could not drink we could not drink you could not drink they could not drink
V-ing form
I could not be drinking you could not be drinking he could not be drinking we could not be drinking you could not be drinking they could not be drinking
Perfect
I could not have drunk you could not have drunk he could not have drunk we could not have drunk you could not have drunk they could not have drunk
V-ing perfect
I could not have been drinking you could not have been drinking he could not have been drinking we could not have been drinking you could not have been drinking they could not have been drinking
Interrogative form
Simple form
could I drink? could you drink? could he drink? could we drink? could you drink? could they drink?
V-ing form
could I be drinking? could you be drinking? could he be drinking? could we be drinking? could you be drinking? could they be drinking?
Perfect
could I have drunk? could you have drunk? could he have drunk? could we have drunk? could you have drunk? could they have drunk?
V-ing perfect
could I have been drinking? could you have been drinking? could he have been drinking? could we have been drinking? could you have been drinking? could they have been drinking?
Interro-negative form
Simple form
could I not drink? could you not drink? could he not drink? could we not drink? could you not drink? could they not drink?
V-ing form
could I not be drinking? could you not be drinking? could he not be drinking? could we not be drinking? could you not be drinking? could they not be drinking?
Perfect
could I not have drunk? could you not have drunk? could he not have drunk? could we not have drunk? could you not have drunk? could they not have drunk?
V-ing perfect
could I not have been drinking? could you not have been drinking? could he not have been drinking? could we not have been drinking? could you not have been drinking? could they not have been drinking?