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 couldn't bicycle you couldn't bicycle he couldn't bicycle we couldn't bicycle you couldn't bicycle they couldn't bicycle
V-ing form
I couldn't be bicycling you couldn't be bicycling he couldn't be bicycling we couldn't be bicycling you couldn't be bicycling they couldn't be bicycling
Perfect
I couldn't have bicycled you couldn't have bicycled he couldn't have bicycled we couldn't have bicycled you couldn't have bicycled they couldn't have bicycled
V-ing perfect
I couldn't have been bicycling you couldn't have been bicycling he couldn't have been bicycling we couldn't have been bicycling you couldn't have been bicycling they couldn't 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
couldn't I bicycle? couldn't you bicycle? couldn't he bicycle? couldn't we bicycle? couldn't you bicycle? couldn't they bicycle?
V-ing form
couldn't I be bicycling? couldn't you be bicycling? couldn't he be bicycling? couldn't we be bicycling? couldn't you be bicycling? couldn't they be bicycling?
Perfect
couldn't I have bicycled? couldn't you have bicycled? couldn't he have bicycled? couldn't we have bicycled? couldn't you have bicycled? couldn't they have bicycled?
V-ing perfect
couldn't I have been bicycling? couldn't you have been bicycling? couldn't he have been bicycling? couldn't we have been bicycling? couldn't you have been bicycling? couldn't they have been bicycling?