I could tabulate you could tabulate he could tabulate we could tabulate you could tabulate they could tabulate
V-ing form
I could be tabulating you could be tabulating he could be tabulating we could be tabulating you could be tabulating they could be tabulating
Perfect
I could have tabulated you could have tabulated he could have tabulated we could have tabulated you could have tabulated they could have tabulated
V-ing perfect
I could have been tabulating you could have been tabulating he could have been tabulating we could have been tabulating you could have been tabulating they could have been tabulating
Negation
Simple form
I couldn't tabulate you couldn't tabulate he couldn't tabulate we couldn't tabulate you couldn't tabulate they couldn't tabulate
V-ing form
I couldn't be tabulating you couldn't be tabulating he couldn't be tabulating we couldn't be tabulating you couldn't be tabulating they couldn't be tabulating
Perfect
I couldn't have tabulated you couldn't have tabulated he couldn't have tabulated we couldn't have tabulated you couldn't have tabulated they couldn't have tabulated
V-ing perfect
I couldn't have been tabulating you couldn't have been tabulating he couldn't have been tabulating we couldn't have been tabulating you couldn't have been tabulating they couldn't have been tabulating
Interrogative form
Simple form
could I tabulate? could you tabulate? could he tabulate? could we tabulate? could you tabulate? could they tabulate?
V-ing form
could I be tabulating? could you be tabulating? could he be tabulating? could we be tabulating? could you be tabulating? could they be tabulating?
Perfect
could I have tabulated? could you have tabulated? could he have tabulated? could we have tabulated? could you have tabulated? could they have tabulated?
V-ing perfect
could I have been tabulating? could you have been tabulating? could he have been tabulating? could we have been tabulating? could you have been tabulating? could they have been tabulating?
Interro-negative form
Simple form
couldn't I tabulate? couldn't you tabulate? couldn't he tabulate? couldn't we tabulate? couldn't you tabulate? couldn't they tabulate?
V-ing form
couldn't I be tabulating? couldn't you be tabulating? couldn't he be tabulating? couldn't we be tabulating? couldn't you be tabulating? couldn't they be tabulating?
Perfect
couldn't I have tabulated? couldn't you have tabulated? couldn't he have tabulated? couldn't we have tabulated? couldn't you have tabulated? couldn't they have tabulated?
V-ing perfect
couldn't I have been tabulating? couldn't you have been tabulating? couldn't he have been tabulating? couldn't we have been tabulating? couldn't you have been tabulating? couldn't they have been tabulating?