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