题干

我国南方某些地区搞的桑基鱼塘是将部分低洼稻田挖深作塘,塘内养鱼;提高并加宽塘基,在塘基上种桑,用来养蚕。这样可以做到蚕粪养鱼,鱼粪肥塘,塘泥肥田、肥桑,从而获得稻、鱼、蚕茧三丰收。这是哪一方面的典型例子

A:提高生态系统的恢复力的稳定性

B:根据人类需要建立新的生态平衡

C:加速生态系统的物质循环

D:提高生态系统的能量传递效率

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答案(点此获取答案解析)

B

同类题5

       America is a mobile society. Friendships between Americans can be close and real, yet disappear soon. They don't feel hurt. If the same two people meet again, even years later, they pick up the friendship. This can be quite difficult for us Chinese to understand. Friendships between us develop more slowly but may become lifelong feelings, extending(延伸)deeply into both families.
      There is another difficult point for us to understand .Although Americans treat friends warmly in their personal everyday lives, they don't show their politeness to them if it requires a great deal of time. But in China, we are usually generous with our time. We, as hosts, will appear at an airport even in the middle of the night to meet a friend. We may take days off from our work to act as guides to our friends: It is opposite in America, Americans cannot manage the time to do a great deal with a visitor outside their daily plans. They will probably expect the visitors to get themselves from the airport to the hotels. And they expect the visitors will phone them from there. Once the visitors arrive at their homes, the welcome will be full, warm and real.
       For Americans, it is often considered more friendly to invite a friend to their homes than to restaurants, except for business matters. Americans are ready to receive us foreigners at their homes, share their holidays, and their home life. So accept their hospitality(好客)at home and enjoy your visit in America!