参考答案

正确答案：C
解析：[听力原文]
What are the two conditions that must exist for thunderstorms to develop?
信息明示题。文章第二段开头指出，the air must contain a great deal of water vapor．．．must be a rapidly rising air current(空气中必须包含大量的水气…还要有快速上升的气流)，由此可知C正确。