V. Fill in each numbered blank with one suitable word or phrase . Acid rain will not be an easy problem(1)……. As more and more countries become …(2)… there will be more and more competition for petroleum for cars, home heating and industry . While ….(3)….petroleum contribute greatly…(4)….acid rain, it is less polluted than coal. Unfortunately, petroleum is more ..(5)…than coal and no one knows  exactly ..(6) … petroleum is left. Therefore, there  will be a pressure to burn coal for energy. Coal is a ..(7) ..dirtier energy source than petroleum. Since we already know how …(8).. acid rain is, it is important ..(9)… we increase our efforts to find a ..(10)…. Source of energy as quickly as possible, so that we can avoid further environmental damage. 1. A. solve                                B. to solve                       C. solved               D. solving 2. A. industry                           B. industrial                    C. industrialize      D. industrialized 3. A. firing                                B. shooting                     C. burning            D. cooking 4. A. to                                     B. for                              C. at                      D. with 5. A. expensive                         B. cheap                          C. clean                 D. dirty 6. A. how many                        B. how much                  C. how far             D. how long 7. A. so                                    B. many                         C. lot                     D. much 8.A. destroy                             B. destroyed                   C. destruction        D. destructive 9. A. that                                  B. if                                C. weather            D. which 10. A. polluted                         B. polluting                    C. non-polluting    D. non- polluted