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