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