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