I could strum you could strum he could strum we could strum you could strum they could strum
V-ing form
I could be strumming you could be strumming he could be strumming we could be strumming you could be strumming they could be strumming
Perfect
I could have strummed you could have strummed he could have strummed we could have strummed you could have strummed they could have strummed
V-ing perfect
I could have been strumming you could have been strumming he could have been strumming we could have been strumming you could have been strumming they could have been strumming
Negation
Simple form
I could not strum you could not strum he could not strum we could not strum you could not strum they could not strum
V-ing form
I could not be strumming you could not be strumming he could not be strumming we could not be strumming you could not be strumming they could not be strumming
Perfect
I could not have strummed you could not have strummed he could not have strummed we could not have strummed you could not have strummed they could not have strummed
V-ing perfect
I could not have been strumming you could not have been strumming he could not have been strumming we could not have been strumming you could not have been strumming they could not have been strumming
Interrogative form
Simple form
could I strum? could you strum? could he strum? could we strum? could you strum? could they strum?
V-ing form
could I be strumming? could you be strumming? could he be strumming? could we be strumming? could you be strumming? could they be strumming?
Perfect
could I have strummed? could you have strummed? could he have strummed? could we have strummed? could you have strummed? could they have strummed?
V-ing perfect
could I have been strumming? could you have been strumming? could he have been strumming? could we have been strumming? could you have been strumming? could they have been strumming?
Interro-negative form
Simple form
could I not strum? could you not strum? could he not strum? could we not strum? could you not strum? could they not strum?
V-ing form
could I not be strumming? could you not be strumming? could he not be strumming? could we not be strumming? could you not be strumming? could they not be strumming?
Perfect
could I not have strummed? could you not have strummed? could he not have strummed? could we not have strummed? could you not have strummed? could they not have strummed?
V-ing perfect
could I not have been strumming? could you not have been strumming? could he not have been strumming? could we not have been strumming? could you not have been strumming? could they not have been strumming?