I could pollute you could pollute she could pollute we could pollute you could pollute they could pollute
V-ing form
I could be polluting you could be polluting she could be polluting we could be polluting you could be polluting they could be polluting
Perfect
I could have polluted you could have polluted she 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 she 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 she 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 she 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 she 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 she 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 she pollute? could we pollute? could you pollute? could they pollute?
V-ing form
could I be polluting? could you be polluting? could she be polluting? could we be polluting? could you be polluting? could they be polluting?
Perfect
could I have polluted? could you have polluted? could she 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 she 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 she 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 she 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 she 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 she have been polluting? couldn't we have been polluting? couldn't you have been polluting? couldn't they have been polluting?