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 couldn't snake you couldn't snake he couldn't snake we couldn't snake you couldn't snake they couldn't snake
V-ing form
I couldn't be snaking you couldn't be snaking he couldn't be snaking we couldn't be snaking you couldn't be snaking they couldn't be snaking
Perfect
I couldn't have snaked you couldn't have snaked he couldn't have snaked we couldn't have snaked you couldn't have snaked they couldn't have snaked
V-ing perfect
I couldn't have been snaking you couldn't have been snaking he couldn't have been snaking we couldn't have been snaking you couldn't have been snaking they couldn't 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
couldn't I snake? couldn't you snake? couldn't he snake? couldn't we snake? couldn't you snake? couldn't they snake?
V-ing form
couldn't I be snaking? couldn't you be snaking? couldn't he be snaking? couldn't we be snaking? couldn't you be snaking? couldn't they be snaking?
Perfect
couldn't I have snaked? couldn't you have snaked? couldn't he have snaked? couldn't we have snaked? couldn't you have snaked? couldn't they have snaked?
V-ing perfect
couldn't I have been snaking? couldn't you have been snaking? couldn't he have been snaking? couldn't we have been snaking? couldn't you have been snaking? couldn't they have been snaking?