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