I could bicycle you could bicycle he could bicycle we could bicycle you could bicycle they could bicycle
V-ing form
I could be bicycling you could be bicycling he could be bicycling we could be bicycling you could be bicycling they could be bicycling
Perfect
I could have bicycled you could have bicycled he could have bicycled we could have bicycled you could have bicycled they could have bicycled
V-ing perfect
I could have been bicycling you could have been bicycling he could have been bicycling we could have been bicycling you could have been bicycling they could have been bicycling
Negation
Simple form
I could not bicycle you could not bicycle he could not bicycle we could not bicycle you could not bicycle they could not bicycle
V-ing form
I could not be bicycling you could not be bicycling he could not be bicycling we could not be bicycling you could not be bicycling they could not be bicycling
Perfect
I could not have bicycled you could not have bicycled he could not have bicycled we could not have bicycled you could not have bicycled they could not have bicycled
V-ing perfect
I could not have been bicycling you could not have been bicycling he could not have been bicycling we could not have been bicycling you could not have been bicycling they could not have been bicycling
Interrogative form
Simple form
could I bicycle? could you bicycle? could he bicycle? could we bicycle? could you bicycle? could they bicycle?
V-ing form
could I be bicycling? could you be bicycling? could he be bicycling? could we be bicycling? could you be bicycling? could they be bicycling?
Perfect
could I have bicycled? could you have bicycled? could he have bicycled? could we have bicycled? could you have bicycled? could they have bicycled?
V-ing perfect
could I have been bicycling? could you have been bicycling? could he have been bicycling? could we have been bicycling? could you have been bicycling? could they have been bicycling?
Interro-negative form
Simple form
could I not bicycle? could you not bicycle? could he not bicycle? could we not bicycle? could you not bicycle? could they not bicycle?
V-ing form
could I not be bicycling? could you not be bicycling? could he not be bicycling? could we not be bicycling? could you not be bicycling? could they not be bicycling?
Perfect
could I not have bicycled? could you not have bicycled? could he not have bicycled? could we not have bicycled? could you not have bicycled? could they not have bicycled?
V-ing perfect
could I not have been bicycling? could you not have been bicycling? could he not have been bicycling? could we not have been bicycling? could you not have been bicycling? could they not have been bicycling?