Something must be done to prevent our city ____ by thick smoke.

A. to be polluted      B. from polluting     C. from being polluted D. polluting

Something must be done to prevent our city ____ by thick smoke.

A. to be polluted      B. from polluting     C. from being polluted D. polluting

Something must be done to prevent our city ____ by thick smoke.

A. to be polluted      B. from polluting     C. from being polluted D. polluting

Something must be done to prevent our city ____ by thick smoke.

A. to be polluted      B. from polluting     C. from being polluted D. polluting

Something must be done to prevent our city ____ by thick smoke.

A. to be polluted      B. from polluting     C. from being polluted D. polluting