I could fossilize you could fossilize she could fossilize we could fossilize you could fossilize they could fossilize
V-ing form
I could be fossilizing you could be fossilizing she could be fossilizing we could be fossilizing you could be fossilizing they could be fossilizing
Perfect
I could have fossilized you could have fossilized she could have fossilized we could have fossilized you could have fossilized they could have fossilized
V-ing perfect
I could have been fossilizing you could have been fossilizing she could have been fossilizing we could have been fossilizing you could have been fossilizing they could have been fossilizing
Negation
Simple form
I could not fossilize you could not fossilize she could not fossilize we could not fossilize you could not fossilize they could not fossilize
V-ing form
I could not be fossilizing you could not be fossilizing she could not be fossilizing we could not be fossilizing you could not be fossilizing they could not be fossilizing
Perfect
I could not have fossilized you could not have fossilized she could not have fossilized we could not have fossilized you could not have fossilized they could not have fossilized
V-ing perfect
I could not have been fossilizing you could not have been fossilizing she could not have been fossilizing we could not have been fossilizing you could not have been fossilizing they could not have been fossilizing
Interrogative form
Simple form
could I fossilize? could you fossilize? could she fossilize? could we fossilize? could you fossilize? could they fossilize?
V-ing form
could I be fossilizing? could you be fossilizing? could she be fossilizing? could we be fossilizing? could you be fossilizing? could they be fossilizing?
Perfect
could I have fossilized? could you have fossilized? could she have fossilized? could we have fossilized? could you have fossilized? could they have fossilized?
V-ing perfect
could I have been fossilizing? could you have been fossilizing? could she have been fossilizing? could we have been fossilizing? could you have been fossilizing? could they have been fossilizing?
Interro-negative form
Simple form
could I not fossilize? could you not fossilize? could she not fossilize? could we not fossilize? could you not fossilize? could they not fossilize?
V-ing form
could I not be fossilizing? could you not be fossilizing? could she not be fossilizing? could we not be fossilizing? could you not be fossilizing? could they not be fossilizing?
Perfect
could I not have fossilized? could you not have fossilized? could she not have fossilized? could we not have fossilized? could you not have fossilized? could they not have fossilized?
V-ing perfect
could I not have been fossilizing? could you not have been fossilizing? could she not have been fossilizing? could we not have been fossilizing? could you not have been fossilizing? could they not have been fossilizing?