7. Solar energy can help us _____ household bills every month.
      A. reduce           B. increase          C. reuse          D. recycle
8. Wind or solar are _____ resources that can supply us with abundant power.
      A. unlimited            B. limited            C. renewable           D. A&C are correct
9. These days it is impossible to open a newspaper_____ reading about the damge we are doing to the evironment.
       A. without             B. with             C. of                D. off
10. Reducing pollution is complicated ______ much pollution is caused by things that bennefit people.
        A. however            B. although             C. because            D. despite