I could witter you could witter he could witter we could witter you could witter they could witter
V-ing form
I could be wittering you could be wittering he could be wittering we could be wittering you could be wittering they could be wittering
Perfect
I could have wittered you could have wittered he could have wittered we could have wittered you could have wittered they could have wittered
V-ing perfect
I could have been wittering you could have been wittering he could have been wittering we could have been wittering you could have been wittering they could have been wittering
Negation
Simple form
I could not witter you could not witter he could not witter we could not witter you could not witter they could not witter
V-ing form
I could not be wittering you could not be wittering he could not be wittering we could not be wittering you could not be wittering they could not be wittering
Perfect
I could not have wittered you could not have wittered he could not have wittered we could not have wittered you could not have wittered they could not have wittered
V-ing perfect
I could not have been wittering you could not have been wittering he could not have been wittering we could not have been wittering you could not have been wittering they could not have been wittering
Interrogative form
Simple form
could I witter? could you witter? could he witter? could we witter? could you witter? could they witter?
V-ing form
could I be wittering? could you be wittering? could he be wittering? could we be wittering? could you be wittering? could they be wittering?
Perfect
could I have wittered? could you have wittered? could he have wittered? could we have wittered? could you have wittered? could they have wittered?
V-ing perfect
could I have been wittering? could you have been wittering? could he have been wittering? could we have been wittering? could you have been wittering? could they have been wittering?
Interro-negative form
Simple form
could I not witter? could you not witter? could he not witter? could we not witter? could you not witter? could they not witter?
V-ing form
could I not be wittering? could you not be wittering? could he not be wittering? could we not be wittering? could you not be wittering? could they not be wittering?
Perfect
could I not have wittered? could you not have wittered? could he not have wittered? could we not have wittered? could you not have wittered? could they not have wittered?
V-ing perfect
could I not have been wittering? could you not have been wittering? could he not have been wittering? could we not have been wittering? could you not have been wittering? could they not have been wittering?