I could bin you could bin he could bin we could bin you could bin they could bin
V-ing form
I could be bining you could be bining he could be bining we could be bining you could be bining they could be bining
Perfect
I could have bined you could have bined he could have bined we could have bined you could have bined they could have bined
V-ing perfect
I could have been bining you could have been bining he could have been bining we could have been bining you could have been bining they could have been bining
Negation
Simple form
I couldn't bin you couldn't bin he couldn't bin we couldn't bin you couldn't bin they couldn't bin
V-ing form
I couldn't be bining you couldn't be bining he couldn't be bining we couldn't be bining you couldn't be bining they couldn't be bining
Perfect
I couldn't have bined you couldn't have bined he couldn't have bined we couldn't have bined you couldn't have bined they couldn't have bined
V-ing perfect
I couldn't have been bining you couldn't have been bining he couldn't have been bining we couldn't have been bining you couldn't have been bining they couldn't have been bining
Interrogative form
Simple form
could I bin? could you bin? could he bin? could we bin? could you bin? could they bin?
V-ing form
could I be bining? could you be bining? could he be bining? could we be bining? could you be bining? could they be bining?
Perfect
could I have bined? could you have bined? could he have bined? could we have bined? could you have bined? could they have bined?
V-ing perfect
could I have been bining? could you have been bining? could he have been bining? could we have been bining? could you have been bining? could they have been bining?
Interro-negative form
Simple form
couldn't I bin? couldn't you bin? couldn't he bin? couldn't we bin? couldn't you bin? couldn't they bin?
V-ing form
couldn't I be bining? couldn't you be bining? couldn't he be bining? couldn't we be bining? couldn't you be bining? couldn't they be bining?
Perfect
couldn't I have bined? couldn't you have bined? couldn't he have bined? couldn't we have bined? couldn't you have bined? couldn't they have bined?
V-ing perfect
couldn't I have been bining? couldn't you have been bining? couldn't he have been bining? couldn't we have been bining? couldn't you have been bining? couldn't they have been bining?