I. Choose the word or phrase (A, B, C or D) that best fits the blank space in the following passage.                 In recent years there have been many (1) ________ on air pollution in newspapers and magazines. Scientists all over the world have warned that our atmosphere is (2) ________ more and more contaminated, and that Man, through his carelessness, may run (3) ____________ of pure air to breathe.                 Automobiles and industries mainly (4) ________ for air pollution in most cities. They pure into the air such gases as carbon monoxide, sulphur and nitrogen oxides, which are very (5) ________ to humans. Worse still, these gases after a series of chemical changes, turn (6) ________ toxic acids. They fall down in ‘acid rain’, raising the acidity in the air, soil and water to dangerous (7) ____________and affecting not only trees but also fish and other wildlife. Many industrial countries in Europe and North America have (8) ________ bad affects from those ‘rains’.                 (9) ________, man faces no more urgent problem than that of saving his own survival. Scientists, social organization and governments should sit down together to solve the air (10) ________ problem. 1. A. programs             B. events   C. articles                            D. columns 2.            A. changing             B. becoming      C. making                            D. taking 3.            A. up        B. over                                 C. away                  D. out 4.            A. bring        B. get                                     C. account                           D. count 5.            A. harmful             B. powerful                        C. awful                               D. painful 6.            A. in              B. into                                   C. out                                    D. over 7.            A. amounts      B. ranks                               C. points                              D. levels 8.            A. suffered        B. influenced                     C. offered                            D. bothered 9.            A. Naturally        B. Safely                              C. Surely                              D. Practically 10.          A. pollute               B. polluted                          C. polluting                         D. pollution