刷题刷出新高度，偷偷领先！偷偷领先！偷偷领先！ 关注我们，悄悄成为最优秀的自己！
单选题
It is hard to track the blue whale, the ocean’s largest creature, which has almost been killed off by commercial whaling and is now listed as an endangered species. Attaching radio devices to itis difficult, and visual sightings are too unreliable to give real insight into its behavior. So biologists were delighted early this year when, with the help of the Navy, they were able to track a particular blue whale for 43 days, monitoring its sounds. This was possible because of the Navy’s formerly top secret system of underwater listening devices spanning the oceans. Tracking whales is but one example of an exciting new world just opening to civilian scientists after the cold war as the Navy starts to share and partly uncover its global network of underwater listening system built Over the decades to track the ships of potential enemies. Earth scientists announced at a news conference recently that they had used the system for closely monitoring a deep-sea volcanic eruption (爆发) for the first time and that they planned similar studies. Other scientists have proposed to use the network for tracking ocean currents and measuring changes in ocean and global temperatures. The speed of sound in water is roughly one mile a second—slower than through land but faster than through air. What is most important is that different layers of ocean water can act as channels for sounds, focusing them in the same way a stethoscope (听诊器) does when it carries faint noises from a patient’s chest to a doctor’s ear. This focusing is the main reason that even relatively weak sounds in the ocean, especially low-frequency ones, can often travel thousands of miles.
The passage is chiefly about ______.
A
B
C
D
使用微信搜索喵呜刷题，轻松应对考试！
答案：
解析：
：本文主要介绍了冷战后海军开始与民间科学家分享其水下监听系统，并描述了该系统在追踪蓝鲸、监测深海火山爆发、追踪洋流和测量海洋及全球温度变化等方面的应用。因此，本文主要讲述的是军事探测系统的民用化，选项B最为符合。
创作类型：
原创
本文链接：The passage is chiefly about ______.
版权声明：本站点所有文章除特别声明外，均采用 CC BY-NC-SA 4.0 许可协议。转载请注明文章出处。让学习像火箭一样快速，微信扫码，获取考试解析、体验刷题服务，开启你的学习加速器！
分享考题 
