I could snake you could snake he could snake we could snake you could snake they could snake
V-ing form
I could be snaking you could be snaking he could be snaking we could be snaking you could be snaking they could be snaking
Perfect
I could have snaked you could have snaked he 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 he 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 he 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 he 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 he 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 he 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 he snake? could we snake? could you snake? could they snake?
V-ing form
could I be snaking? could you be snaking? could he be snaking? could we be snaking? could you be snaking? could they be snaking?
Perfect
could I have snaked? could you have snaked? could he 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 he 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 he 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 he 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 he 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 he not have been snaking? could we not have been snaking? could you not have been snaking? could they not have been snaking?