More and more people have realized that we won’t have cleaner water to drink unless something _______soon.

A. is done   B. was done   C. will be done   D. to be done

More and more people have realized we won’t have cleaner water to drink unless something ________ soon．

1. A.
   was done
2. B.
   will be done
3. C.
   to be done
4. D.
   is done

More and more people have realized we won’t have cleaner water to drink unless something______ soon．

A．is done          B．will be done          C．to be done            D．was done