I could oversleep you could oversleep she could oversleep we could oversleep you could oversleep they could oversleep
V-ing form
I could be oversleeping you could be oversleeping she could be oversleeping we could be oversleeping you could be oversleeping they could be oversleeping
Perfect
I could have overslept you could have overslept she could have overslept we could have overslept you could have overslept they could have overslept
V-ing perfect
I could have been oversleeping you could have been oversleeping she could have been oversleeping we could have been oversleeping you could have been oversleeping they could have been oversleeping
Negation
Simple form
I couldn't oversleep you couldn't oversleep she couldn't oversleep we couldn't oversleep you couldn't oversleep they couldn't oversleep
V-ing form
I couldn't be oversleeping you couldn't be oversleeping she couldn't be oversleeping we couldn't be oversleeping you couldn't be oversleeping they couldn't be oversleeping
Perfect
I couldn't have overslept you couldn't have overslept she couldn't have overslept we couldn't have overslept you couldn't have overslept they couldn't have overslept
V-ing perfect
I couldn't have been oversleeping you couldn't have been oversleeping she couldn't have been oversleeping we couldn't have been oversleeping you couldn't have been oversleeping they couldn't have been oversleeping
Interrogative form
Simple form
could I oversleep? could you oversleep? could she oversleep? could we oversleep? could you oversleep? could they oversleep?
V-ing form
could I be oversleeping? could you be oversleeping? could she be oversleeping? could we be oversleeping? could you be oversleeping? could they be oversleeping?
Perfect
could I have overslept? could you have overslept? could she have overslept? could we have overslept? could you have overslept? could they have overslept?
V-ing perfect
could I have been oversleeping? could you have been oversleeping? could she have been oversleeping? could we have been oversleeping? could you have been oversleeping? could they have been oversleeping?
Interro-negative form
Simple form
couldn't I oversleep? couldn't you oversleep? couldn't she oversleep? couldn't we oversleep? couldn't you oversleep? couldn't they oversleep?
V-ing form
couldn't I be oversleeping? couldn't you be oversleeping? couldn't she be oversleeping? couldn't we be oversleeping? couldn't you be oversleeping? couldn't they be oversleeping?
Perfect
couldn't I have overslept? couldn't you have overslept? couldn't she have overslept? couldn't we have overslept? couldn't you have overslept? couldn't they have overslept?
V-ing perfect
couldn't I have been oversleeping? couldn't you have been oversleeping? couldn't she have been oversleeping? couldn't we have been oversleeping? couldn't you have been oversleeping? couldn't they have been oversleeping?