I could blackberry you could blackberry he could blackberry we could blackberry you could blackberry they could blackberry
V-ing form
I could be blackberrying you could be blackberrying he could be blackberrying we could be blackberrying you could be blackberrying they could be blackberrying
Perfect
I could have blackberried you could have blackberried he could have blackberried we could have blackberried you could have blackberried they could have blackberried
V-ing perfect
I could have been blackberrying you could have been blackberrying he could have been blackberrying we could have been blackberrying you could have been blackberrying they could have been blackberrying
Negation
Simple form
I could not blackberry you could not blackberry he could not blackberry we could not blackberry you could not blackberry they could not blackberry
V-ing form
I could not be blackberrying you could not be blackberrying he could not be blackberrying we could not be blackberrying you could not be blackberrying they could not be blackberrying
Perfect
I could not have blackberried you could not have blackberried he could not have blackberried we could not have blackberried you could not have blackberried they could not have blackberried
V-ing perfect
I could not have been blackberrying you could not have been blackberrying he could not have been blackberrying we could not have been blackberrying you could not have been blackberrying they could not have been blackberrying
Interrogative form
Simple form
could I blackberry? could you blackberry? could he blackberry? could we blackberry? could you blackberry? could they blackberry?
V-ing form
could I be blackberrying? could you be blackberrying? could he be blackberrying? could we be blackberrying? could you be blackberrying? could they be blackberrying?
Perfect
could I have blackberried? could you have blackberried? could he have blackberried? could we have blackberried? could you have blackberried? could they have blackberried?
V-ing perfect
could I have been blackberrying? could you have been blackberrying? could he have been blackberrying? could we have been blackberrying? could you have been blackberrying? could they have been blackberrying?
Interro-negative form
Simple form
could I not blackberry? could you not blackberry? could he not blackberry? could we not blackberry? could you not blackberry? could they not blackberry?
V-ing form
could I not be blackberrying? could you not be blackberrying? could he not be blackberrying? could we not be blackberrying? could you not be blackberrying? could they not be blackberrying?
Perfect
could I not have blackberried? could you not have blackberried? could he not have blackberried? could we not have blackberried? could you not have blackberried? could they not have blackberried?
V-ing perfect
could I not have been blackberrying? could you not have been blackberrying? could he not have been blackberrying? could we not have been blackberrying? could you not have been blackberrying? could they not have been blackberrying?