第一部分 阅读理解（共两节，满分40分）
第一节（共15小题；每小题2分，满分30分）
阅读下列短文，从每题所给的四个选项中（A、B、C、D）中，选出最佳选项。
A
Is there link between humans and climate change or not? This question was first studied in the early 1900s. Since then, many scientists have thought that our actions do make a difference. In 1997, the Kyoto Protocol explained our role in the Earth’s changing atmosphere and set international limits for gas emissions(排放) from 2008 to 2012. Some countries have decided to continue these reductions until 2020.
