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