I could vein you could vein he could vein we could vein you could vein they could vein
V-ing form
I could be veining you could be veining he could be veining we could be veining you could be veining they could be veining
Perfect
I could have veined you could have veined he could have veined we could have veined you could have veined they could have veined
V-ing perfect
I could have been veining you could have been veining he could have been veining we could have been veining you could have been veining they could have been veining
Negation
Simple form
I could not vein you could not vein he could not vein we could not vein you could not vein they could not vein
V-ing form
I could not be veining you could not be veining he could not be veining we could not be veining you could not be veining they could not be veining
Perfect
I could not have veined you could not have veined he could not have veined we could not have veined you could not have veined they could not have veined
V-ing perfect
I could not have been veining you could not have been veining he could not have been veining we could not have been veining you could not have been veining they could not have been veining
Interrogative form
Simple form
could I vein? could you vein? could he vein? could we vein? could you vein? could they vein?
V-ing form
could I be veining? could you be veining? could he be veining? could we be veining? could you be veining? could they be veining?
Perfect
could I have veined? could you have veined? could he have veined? could we have veined? could you have veined? could they have veined?
V-ing perfect
could I have been veining? could you have been veining? could he have been veining? could we have been veining? could you have been veining? could they have been veining?
Interro-negative form
Simple form
could I not vein? could you not vein? could he not vein? could we not vein? could you not vein? could they not vein?
V-ing form
could I not be veining? could you not be veining? could he not be veining? could we not be veining? could you not be veining? could they not be veining?
Perfect
could I not have veined? could you not have veined? could he not have veined? could we not have veined? could you not have veined? could they not have veined?
V-ing perfect
could I not have been veining? could you not have been veining? could he not have been veining? could we not have been veining? could you not have been veining? could they not have been veining?