I could persist you could persist he could persist we could persist you could persist they could persist
V-ing form
I could be persisting you could be persisting he could be persisting we could be persisting you could be persisting they could be persisting
Perfect
I could have persisted you could have persisted he could have persisted we could have persisted you could have persisted they could have persisted
V-ing perfect
I could have been persisting you could have been persisting he could have been persisting we could have been persisting you could have been persisting they could have been persisting
Negation
Simple form
I could not persist you could not persist he could not persist we could not persist you could not persist they could not persist
V-ing form
I could not be persisting you could not be persisting he could not be persisting we could not be persisting you could not be persisting they could not be persisting
Perfect
I could not have persisted you could not have persisted he could not have persisted we could not have persisted you could not have persisted they could not have persisted
V-ing perfect
I could not have been persisting you could not have been persisting he could not have been persisting we could not have been persisting you could not have been persisting they could not have been persisting
Interrogative form
Simple form
could I persist? could you persist? could he persist? could we persist? could you persist? could they persist?
V-ing form
could I be persisting? could you be persisting? could he be persisting? could we be persisting? could you be persisting? could they be persisting?
Perfect
could I have persisted? could you have persisted? could he have persisted? could we have persisted? could you have persisted? could they have persisted?
V-ing perfect
could I have been persisting? could you have been persisting? could he have been persisting? could we have been persisting? could you have been persisting? could they have been persisting?
Interro-negative form
Simple form
could I not persist? could you not persist? could he not persist? could we not persist? could you not persist? could they not persist?
V-ing form
could I not be persisting? could you not be persisting? could he not be persisting? could we not be persisting? could you not be persisting? could they not be persisting?
Perfect
could I not have persisted? could you not have persisted? could he not have persisted? could we not have persisted? could you not have persisted? could they not have persisted?
V-ing perfect
could I not have been persisting? could you not have been persisting? could he not have been persisting? could we not have been persisting? could you not have been persisting? could they not have been persisting?