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