(单选题)

The author argues that the rising carbon levels in rain forests may ______.

A.turn them into a major source of greenhouse gases

B.change the weather patterns throughout the world leaves

C.pose a threat to wildlife

D.accelerate their collapse

参考答案：A

参考解析：

推理判断题。根据第二段最后一句“If the collapse of the rain forests speeds up dramatically, it could eventually release 3.5—5 billion metric tons of carbon into the atmosphere each year, making forests the leading source of greenhouse gases”可知，如果热带雨林的坍塌速度加快，最终每年会向大气释放3.5—5亿公吨的碳，使森林成为温室气体的主要来源。由此可知，热带雨林中不断上升的碳含量可能会使它们成为温室气体的主要来源。故选A。

知识点：阅读理解四选一英语专业基础知识阅读理解教师招聘-小学英语