I could winter you could winter he could winter we could winter you could winter they could winter
V-ing form
I could be wintering you could be wintering he could be wintering we could be wintering you could be wintering they could be wintering
Perfect
I could have wintered you could have wintered he could have wintered we could have wintered you could have wintered they could have wintered
V-ing perfect
I could have been wintering you could have been wintering he could have been wintering we could have been wintering you could have been wintering they could have been wintering
Negation
Simple form
I could not winter you could not winter he could not winter we could not winter you could not winter they could not winter
V-ing form
I could not be wintering you could not be wintering he could not be wintering we could not be wintering you could not be wintering they could not be wintering
Perfect
I could not have wintered you could not have wintered he could not have wintered we could not have wintered you could not have wintered they could not have wintered
V-ing perfect
I could not have been wintering you could not have been wintering he could not have been wintering we could not have been wintering you could not have been wintering they could not have been wintering
Interrogative form
Simple form
could I winter? could you winter? could he winter? could we winter? could you winter? could they winter?
V-ing form
could I be wintering? could you be wintering? could he be wintering? could we be wintering? could you be wintering? could they be wintering?
Perfect
could I have wintered? could you have wintered? could he have wintered? could we have wintered? could you have wintered? could they have wintered?
V-ing perfect
could I have been wintering? could you have been wintering? could he have been wintering? could we have been wintering? could you have been wintering? could they have been wintering?
Interro-negative form
Simple form
could I not winter? could you not winter? could he not winter? could we not winter? could you not winter? could they not winter?
V-ing form
could I not be wintering? could you not be wintering? could he not be wintering? could we not be wintering? could you not be wintering? could they not be wintering?
Perfect
could I not have wintered? could you not have wintered? could he not have wintered? could we not have wintered? could you not have wintered? could they not have wintered?
V-ing perfect
could I not have been wintering? could you not have been wintering? could he not have been wintering? could we not have been wintering? could you not have been wintering? could they not have been wintering?