I could catch you could catch he could catch we could catch you could catch they could catch
V-ing form
I could be catching you could be catching he could be catching we could be catching you could be catching they could be catching
Perfect
I could have caught you could have caught he could have caught we could have caught you could have caught they could have caught
V-ing perfect
I could have been catching you could have been catching he could have been catching we could have been catching you could have been catching they could have been catching
Negation
Simple form
I could not catch you could not catch he could not catch we could not catch you could not catch they could not catch
V-ing form
I could not be catching you could not be catching he could not be catching we could not be catching you could not be catching they could not be catching
Perfect
I could not have caught you could not have caught he could not have caught we could not have caught you could not have caught they could not have caught
V-ing perfect
I could not have been catching you could not have been catching he could not have been catching we could not have been catching you could not have been catching they could not have been catching
Interrogative form
Simple form
could I catch? could you catch? could he catch? could we catch? could you catch? could they catch?
V-ing form
could I be catching? could you be catching? could he be catching? could we be catching? could you be catching? could they be catching?
Perfect
could I have caught? could you have caught? could he have caught? could we have caught? could you have caught? could they have caught?
V-ing perfect
could I have been catching? could you have been catching? could he have been catching? could we have been catching? could you have been catching? could they have been catching?
Interro-negative form
Simple form
could I not catch? could you not catch? could he not catch? could we not catch? could you not catch? could they not catch?
V-ing form
could I not be catching? could you not be catching? could he not be catching? could we not be catching? could you not be catching? could they not be catching?
Perfect
could I not have caught? could you not have caught? could he not have caught? could we not have caught? could you not have caught? could they not have caught?
V-ing perfect
could I not have been catching? could you not have been catching? could he not have been catching? could we not have been catching? could you not have been catching? could they not have been catching?