I could earn you could earn he could earn we could earn you could earn they could earn
V-ing form
I could be earning you could be earning he could be earning we could be earning you could be earning they could be earning
Perfect
I could have earned you could have earned he could have earned we could have earned you could have earned they could have earned
V-ing perfect
I could have been earning you could have been earning he could have been earning we could have been earning you could have been earning they could have been earning
Negation
Simple form
I could not earn you could not earn he could not earn we could not earn you could not earn they could not earn
V-ing form
I could not be earning you could not be earning he could not be earning we could not be earning you could not be earning they could not be earning
Perfect
I could not have earned you could not have earned he could not have earned we could not have earned you could not have earned they could not have earned
V-ing perfect
I could not have been earning you could not have been earning he could not have been earning we could not have been earning you could not have been earning they could not have been earning
Interrogative form
Simple form
could I earn? could you earn? could he earn? could we earn? could you earn? could they earn?
V-ing form
could I be earning? could you be earning? could he be earning? could we be earning? could you be earning? could they be earning?
Perfect
could I have earned? could you have earned? could he have earned? could we have earned? could you have earned? could they have earned?
V-ing perfect
could I have been earning? could you have been earning? could he have been earning? could we have been earning? could you have been earning? could they have been earning?
Interro-negative form
Simple form
could I not earn? could you not earn? could he not earn? could we not earn? could you not earn? could they not earn?
V-ing form
could I not be earning? could you not be earning? could he not be earning? could we not be earning? could you not be earning? could they not be earning?
Perfect
could I not have earned? could you not have earned? could he not have earned? could we not have earned? could you not have earned? could they not have earned?
V-ing perfect
could I not have been earning? could you not have been earning? could he not have been earning? could we not have been earning? could you not have been earning? could they not have been earning?