题干

据长江水产研究所确认,2013年葛洲坝附近唯一的自然产卵场中的中华鲟没有繁殖产卵。葛洲坝建成后的几年里,中华鲟野生种群的数量从70年代的1万余尾减少到目前的57尾。下图为中华鲟产卵区分布变化示意图。

根据材料和所知识,分析中华鲟数量锐减的原因并提出保护对策。

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答案(点此获取答案解析)

原因:葛洲坝工程建设时破坏了中华鲟的产卵等生存环境;长江中下游水体污染严重导致幼鱼大量死亡;渔民过度捕捞。

对策:建大坝等水利工程要注意保护生态环境;防治水污染;严禁捕杀;做好保护中华鲟的宣传工作,建立自然保护区。

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    I fell in love with Yosemite National Park the first time I saw it, when I was 13. My parents took us there for camping. On the way out, I asked them to wait while I ran up to E1 Capitan, a1 rock of 3,300 feet straight up. I touched that giant rock and knew 2 I wanted to climb it. That has been my life's passion (钟爱) ever since—3 the rocks and mountains of Yosemite. I've long made Yosemite my 4.

    About 15 years ago I started seeing a lot of 5 like toilet paper, beer cans, and empty boxes, around the area. It's6 me why visitors started respecting the place 7 and treated such a beautiful home-like place this way.

    I tried 8 trash (垃圾) myself, but the job was too big. I would9 an hour or two on the job, only to find the area trashed all over again weeks later. Finally, I got so 10 it that I decided something had to change.

    As a rock-climbing guide, I knew 11about organizing any big event. But in 2014, together with some climbers, I set a date for a 12. On that day, more than 300 people 13 Over three days we collected about 6,000 pounds of trash. It was amazing how much we were able to14 I couldn't believe the15we made —the park looked clean!

    Each year volunteers come for the cleanup from everywhere. In 2016 alone, 2,945 people picked up 42,330 pounds of trash and16132 miles of roadway.

    I often hear people17about their surroundings. If you are one of them, I would say the only way to change things is by 18rather than complaining. We need to teach by 19.You can't blame others 20 you start with yourself.