I could prefertilize you could prefertilize he could prefertilize we could prefertilize you could prefertilize they could prefertilize
V-ing form
I could be prefertilizing you could be prefertilizing he could be prefertilizing we could be prefertilizing you could be prefertilizing they could be prefertilizing
Perfect
I could have prefertilized you could have prefertilized he could have prefertilized we could have prefertilized you could have prefertilized they could have prefertilized
V-ing perfect
I could have been prefertilizing you could have been prefertilizing he could have been prefertilizing we could have been prefertilizing you could have been prefertilizing they could have been prefertilizing
Negation
Simple form
I couldn't prefertilize you couldn't prefertilize he couldn't prefertilize we couldn't prefertilize you couldn't prefertilize they couldn't prefertilize
V-ing form
I couldn't be prefertilizing you couldn't be prefertilizing he couldn't be prefertilizing we couldn't be prefertilizing you couldn't be prefertilizing they couldn't be prefertilizing
Perfect
I couldn't have prefertilized you couldn't have prefertilized he couldn't have prefertilized we couldn't have prefertilized you couldn't have prefertilized they couldn't have prefertilized
V-ing perfect
I couldn't have been prefertilizing you couldn't have been prefertilizing he couldn't have been prefertilizing we couldn't have been prefertilizing you couldn't have been prefertilizing they couldn't have been prefertilizing
Interrogative form
Simple form
could I prefertilize? could you prefertilize? could he prefertilize? could we prefertilize? could you prefertilize? could they prefertilize?
V-ing form
could I be prefertilizing? could you be prefertilizing? could he be prefertilizing? could we be prefertilizing? could you be prefertilizing? could they be prefertilizing?
Perfect
could I have prefertilized? could you have prefertilized? could he have prefertilized? could we have prefertilized? could you have prefertilized? could they have prefertilized?
V-ing perfect
could I have been prefertilizing? could you have been prefertilizing? could he have been prefertilizing? could we have been prefertilizing? could you have been prefertilizing? could they have been prefertilizing?
Interro-negative form
Simple form
couldn't I prefertilize? couldn't you prefertilize? couldn't he prefertilize? couldn't we prefertilize? couldn't you prefertilize? couldn't they prefertilize?
V-ing form
couldn't I be prefertilizing? couldn't you be prefertilizing? couldn't he be prefertilizing? couldn't we be prefertilizing? couldn't you be prefertilizing? couldn't they be prefertilizing?
Perfect
couldn't I have prefertilized? couldn't you have prefertilized? couldn't he have prefertilized? couldn't we have prefertilized? couldn't you have prefertilized? couldn't they have prefertilized?
V-ing perfect
couldn't I have been prefertilizing? couldn't you have been prefertilizing? couldn't he have been prefertilizing? couldn't we have been prefertilizing? couldn't you have been prefertilizing? couldn't they have been prefertilizing?