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