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