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