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