单语范例（未经PONS编辑处理）
Global warming is the effect of too many greenhouse gasses trapped in the air that hold in heat.
en.wikipedia.org Suddenly the hockey stick, the poster-child of the global warming community, turns out to be an artifact of poor mathematics.
en.wikipedia.org Their data is one source of evidence for global warming.
en.wikipedia.org However, the major expansion did not occur until 1980 when global warming caused a significant increase in temperature in the northern hemisphere.
en.wikipedia.org He recognizes the presence of global warming but suggests that human action has little to do with it.
en.wikipedia.org