I could snake you could snake she could snake we could snake you could snake they could snake
V-ing form
I could be snaking you could be snaking she could be snaking we could be snaking you could be snaking they could be snaking
Perfect
I could have snaked you could have snaked she could have snaked we could have snaked you could have snaked they could have snaked
V-ing perfect
I could have been snaking you could have been snaking she could have been snaking we could have been snaking you could have been snaking they could have been snaking
Negation
Simple form
I could not snake you could not snake she could not snake we could not snake you could not snake they could not snake
V-ing form
I could not be snaking you could not be snaking she could not be snaking we could not be snaking you could not be snaking they could not be snaking
Perfect
I could not have snaked you could not have snaked she could not have snaked we could not have snaked you could not have snaked they could not have snaked
V-ing perfect
I could not have been snaking you could not have been snaking she could not have been snaking we could not have been snaking you could not have been snaking they could not have been snaking
Interrogative form
Simple form
could I snake? could you snake? could she snake? could we snake? could you snake? could they snake?
V-ing form
could I be snaking? could you be snaking? could she be snaking? could we be snaking? could you be snaking? could they be snaking?
Perfect
could I have snaked? could you have snaked? could she have snaked? could we have snaked? could you have snaked? could they have snaked?
V-ing perfect
could I have been snaking? could you have been snaking? could she have been snaking? could we have been snaking? could you have been snaking? could they have been snaking?
Interro-negative form
Simple form
could I not snake? could you not snake? could she not snake? could we not snake? could you not snake? could they not snake?
V-ing form
could I not be snaking? could you not be snaking? could she not be snaking? could we not be snaking? could you not be snaking? could they not be snaking?
Perfect
could I not have snaked? could you not have snaked? could she not have snaked? could we not have snaked? could you not have snaked? could they not have snaked?
V-ing perfect
could I not have been snaking? could you not have been snaking? could she not have been snaking? could we not have been snaking? could you not have been snaking? could they not have been snaking?