I could pass you could pass she could pass we could pass you could pass they could pass
V-ing form
I could be passing you could be passing she could be passing we could be passing you could be passing they could be passing
Perfect
I could have passed you could have passed she could have passed we could have passed you could have passed they could have passed
V-ing perfect
I could have been passing you could have been passing she could have been passing we could have been passing you could have been passing they could have been passing
Negation
Simple form
I could not pass you could not pass she could not pass we could not pass you could not pass they could not pass
V-ing form
I could not be passing you could not be passing she could not be passing we could not be passing you could not be passing they could not be passing
Perfect
I could not have passed you could not have passed she could not have passed we could not have passed you could not have passed they could not have passed
V-ing perfect
I could not have been passing you could not have been passing she could not have been passing we could not have been passing you could not have been passing they could not have been passing
Interrogative form
Simple form
could I pass? could you pass? could she pass? could we pass? could you pass? could they pass?
V-ing form
could I be passing? could you be passing? could she be passing? could we be passing? could you be passing? could they be passing?
Perfect
could I have passed? could you have passed? could she have passed? could we have passed? could you have passed? could they have passed?
V-ing perfect
could I have been passing? could you have been passing? could she have been passing? could we have been passing? could you have been passing? could they have been passing?
Interro-negative form
Simple form
could I not pass? could you not pass? could she not pass? could we not pass? could you not pass? could they not pass?
V-ing form
could I not be passing? could you not be passing? could she not be passing? could we not be passing? could you not be passing? could they not be passing?
Perfect
could I not have passed? could you not have passed? could she not have passed? could we not have passed? could you not have passed? could they not have passed?
V-ing perfect
could I not have been passing? could you not have been passing? could she not have been passing? could we not have been passing? could you not have been passing? could they not have been passing?