气温年较差是一个地区最高月均温与最低月均温的差值。下图为世界各地气温年较差分布示意图（单位℃），图中虚线表示水稻种植的北限。读图完成1—3题。
1、对世界各地气温年较差分布的描述正确的是 [ ]
A．暖流流经的海区气温年较差小
B．气温年较差总是由赤道向两极递增
C．热带沙漠地区气温年较差最大
D．赤道地区气温年较差最小
2、图中从甲到乙一线气温年较差变化快的主要原因可能是 [ ]
A．季风气候的影响
B．太阳高度角的年变化幅度大
C．冷暖洋流的影响
D．海陆位置和地形的共同影响
3、图中丙处是北半球水稻种植纬度最高的地区，产生这一现象的气候原因是 [ ]
A．气温的年较差较大
B．受季风影响，夏季高温多雨
C．土壤肥沃，水源充足
D．濒临海洋，全年降水量大
1、D
2、D
3、B
11-15
| 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 it is 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 33 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 plan 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, 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．an effort to protect an endangered marine species
B．the civilian use of a military detection system
C．the exposure of a U.S. Navy top-secret weapon
D．a new way to look into the behavior of blue whales