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