第7题: [单项选择]What does the passage mainly discuss A. The equipment divers use. B. The effects of pressure on gases in the human body. C. How to prepare for a deep dive. D. The symptoms of nitrogen bubbles in the bloodstream. 参考答案:B 答案解析:[试题分析] 文章主旨题。
[详细解答] 文章第一段提出话题,接下来通过原理结合实际来讲述压力的改变对身体的影响。还详细介绍了潜水过程中,下潜和上升过程中会出现的情况,因此,答案为 B较为合理。