【正确答案】 D

【答案解析】本题为事实理解题.由第一段"Air and water pollution, oil spills, and toxic waste are some of the serious problems"和第二段"Pollution in one place often affects areas far away. For example, an accident in a nuclear power plant in one country can create a radioactive cloud that goes halfway around the world. Factory smoke in one country can cause acid rain in another. it is easy to see how our protecting the environment has become an international issue"可以得出正确答案为D。