I could spur you could spur he could spur we could spur you could spur they could spur
V-ing form
I could be spurring you could be spurring he could be spurring we could be spurring you could be spurring they could be spurring
Perfect
I could have spurred you could have spurred he could have spurred we could have spurred you could have spurred they could have spurred
V-ing perfect
I could have been spurring you could have been spurring he could have been spurring we could have been spurring you could have been spurring they could have been spurring
Negation
Simple form
I could not spur you could not spur he could not spur we could not spur you could not spur they could not spur
V-ing form
I could not be spurring you could not be spurring he could not be spurring we could not be spurring you could not be spurring they could not be spurring
Perfect
I could not have spurred you could not have spurred he could not have spurred we could not have spurred you could not have spurred they could not have spurred
V-ing perfect
I could not have been spurring you could not have been spurring he could not have been spurring we could not have been spurring you could not have been spurring they could not have been spurring
Interrogative form
Simple form
could I spur? could you spur? could he spur? could we spur? could you spur? could they spur?
V-ing form
could I be spurring? could you be spurring? could he be spurring? could we be spurring? could you be spurring? could they be spurring?
Perfect
could I have spurred? could you have spurred? could he have spurred? could we have spurred? could you have spurred? could they have spurred?
V-ing perfect
could I have been spurring? could you have been spurring? could he have been spurring? could we have been spurring? could you have been spurring? could they have been spurring?
Interro-negative form
Simple form
could I not spur? could you not spur? could he not spur? could we not spur? could you not spur? could they not spur?
V-ing form
could I not be spurring? could you not be spurring? could he not be spurring? could we not be spurring? could you not be spurring? could they not be spurring?
Perfect
could I not have spurred? could you not have spurred? could he not have spurred? could we not have spurred? could you not have spurred? could they not have spurred?
V-ing perfect
could I not have been spurring? could you not have been spurring? could he not have been spurring? could we not have been spurring? could you not have been spurring? could they not have been spurring?