I could vein you could vein she could vein we could vein you could vein they could vein
V-ing form
I could be veining you could be veining she could be veining we could be veining you could be veining they could be veining
Perfect
I could have veined you could have veined she 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 she could have been veining we could have been veining you could have been veining they could have been veining
Negation
Simple form
I couldn't vein you couldn't vein she couldn't vein we couldn't vein you couldn't vein they couldn't vein
V-ing form
I couldn't be veining you couldn't be veining she couldn't be veining we couldn't be veining you couldn't be veining they couldn't be veining
Perfect
I couldn't have veined you couldn't have veined she couldn't have veined we couldn't have veined you couldn't have veined they couldn't have veined
V-ing perfect
I couldn't have been veining you couldn't have been veining she couldn't have been veining we couldn't have been veining you couldn't have been veining they couldn't have been veining
Interrogative form
Simple form
could I vein? could you vein? could she vein? could we vein? could you vein? could they vein?
V-ing form
could I be veining? could you be veining? could she be veining? could we be veining? could you be veining? could they be veining?
Perfect
could I have veined? could you have veined? could she 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 she have been veining? could we have been veining? could you have been veining? could they have been veining?
Interro-negative form
Simple form
couldn't I vein? couldn't you vein? couldn't she vein? couldn't we vein? couldn't you vein? couldn't they vein?
V-ing form
couldn't I be veining? couldn't you be veining? couldn't she be veining? couldn't we be veining? couldn't you be veining? couldn't they be veining?
Perfect
couldn't I have veined? couldn't you have veined? couldn't she have veined? couldn't we have veined? couldn't you have veined? couldn't they have veined?
V-ing perfect
couldn't I have been veining? couldn't you have been veining? couldn't she have been veining? couldn't we have been veining? couldn't you have been veining? couldn't they have been veining?