I could bike you could bike he could bike we could bike you could bike they could bike
V-ing form
I could be biking you could be biking he could be biking we could be biking you could be biking they could be biking
Perfect
I could have biked you could have biked he could have biked we could have biked you could have biked they could have biked
V-ing perfect
I could have been biking you could have been biking he could have been biking we could have been biking you could have been biking they could have been biking
Negation
Simple form
I could not bike you could not bike he could not bike we could not bike you could not bike they could not bike
V-ing form
I could not be biking you could not be biking he could not be biking we could not be biking you could not be biking they could not be biking
Perfect
I could not have biked you could not have biked he could not have biked we could not have biked you could not have biked they could not have biked
V-ing perfect
I could not have been biking you could not have been biking he could not have been biking we could not have been biking you could not have been biking they could not have been biking
Interrogative form
Simple form
could I bike? could you bike? could he bike? could we bike? could you bike? could they bike?
V-ing form
could I be biking? could you be biking? could he be biking? could we be biking? could you be biking? could they be biking?
Perfect
could I have biked? could you have biked? could he have biked? could we have biked? could you have biked? could they have biked?
V-ing perfect
could I have been biking? could you have been biking? could he have been biking? could we have been biking? could you have been biking? could they have been biking?
Interro-negative form
Simple form
could I not bike? could you not bike? could he not bike? could we not bike? could you not bike? could they not bike?
V-ing form
could I not be biking? could you not be biking? could he not be biking? could we not be biking? could you not be biking? could they not be biking?
Perfect
could I not have biked? could you not have biked? could he not have biked? could we not have biked? could you not have biked? could they not have biked?
V-ing perfect
could I not have been biking? could you not have been biking? could he not have been biking? could we not have been biking? could you not have been biking? could they not have been biking?