Questions 14 to 16 are based on the following passage. At the end of the passage, you will be given 15 seconds to answer the questions. Now listen to the passage. Why can’t man prevent the world from being polluted
A．It’s because there are many developing nations. B．It’s because people use too many man-made materials. C．It’s because we have more and more industry. D．It’s because we are building more vehicles.