I could sneak you could sneak he could sneak we could sneak you could sneak they could sneak
V-ing form
I could be sneaking you could be sneaking he could be sneaking we could be sneaking you could be sneaking they could be sneaking
Perfect
I could have snuck you could have snuck he could have snuck we could have snuck you could have snuck they could have snuck
V-ing perfect
I could have been sneaking you could have been sneaking he could have been sneaking we could have been sneaking you could have been sneaking they could have been sneaking
Negation
Simple form
I could not sneak you could not sneak he could not sneak we could not sneak you could not sneak they could not sneak
V-ing form
I could not be sneaking you could not be sneaking he could not be sneaking we could not be sneaking you could not be sneaking they could not be sneaking
Perfect
I could not have snuck you could not have snuck he could not have snuck we could not have snuck you could not have snuck they could not have snuck
V-ing perfect
I could not have been sneaking you could not have been sneaking he could not have been sneaking we could not have been sneaking you could not have been sneaking they could not have been sneaking
Interrogative form
Simple form
could I sneak? could you sneak? could he sneak? could we sneak? could you sneak? could they sneak?
V-ing form
could I be sneaking? could you be sneaking? could he be sneaking? could we be sneaking? could you be sneaking? could they be sneaking?
Perfect
could I have snuck? could you have snuck? could he have snuck? could we have snuck? could you have snuck? could they have snuck?
V-ing perfect
could I have been sneaking? could you have been sneaking? could he have been sneaking? could we have been sneaking? could you have been sneaking? could they have been sneaking?
Interro-negative form
Simple form
could I not sneak? could you not sneak? could he not sneak? could we not sneak? could you not sneak? could they not sneak?
V-ing form
could I not be sneaking? could you not be sneaking? could he not be sneaking? could we not be sneaking? could you not be sneaking? could they not be sneaking?
Perfect
could I not have snuck? could you not have snuck? could he not have snuck? could we not have snuck? could you not have snuck? could they not have snuck?
V-ing perfect
could I not have been sneaking? could you not have been sneaking? could he not have been sneaking? could we not have been sneaking? could you not have been sneaking? could they not have been sneaking?