题干

关于长江和黄河的叙述,正确的是(    )

①都发源于青藏高原,都流经了三级阶梯;

②长江是我国第一大河,黄河是我国笫二大河;

③长江中下游以湖口为界,黄河中下游以河口为界;

④水能资源方面,长江集中在上游河段,黄河集中在上中游;

⑤都属于外流河,长江水量大无结冰期,黄河含沙量大有凌汛.

A:①②③④⑤

B:①②③

C:③④⑤

D:①④⑤

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答案(点此获取答案解析)

D

同类题5

          The production of coffee beans is a huge, profitable business, but, unfortunately, full-sun production is taking over the industry and
 bringing about a lot of damage. The change in how coffee is grown from shade-grown,production to full-sun production endangers the very existence of, certain animals and birds, and even disturbs the world’s ecological balance.
          On a local level, the damage of the forest required by full-sun fields affects the area’s birds and animals. The shade of the forest trees provides a home for birds and other special(物种) that depend on the trees’ flowers and fruits. Full-sun coffee growers destroy this forest home. As a result, many special are quickly dying out.
        On a more global level, the destruction of the rainforest for full-sun coffee fields also threatens(威胁)human life. Medical research often makes use of the forests' plant and animal life, and the destruction of such species could prevent researchers from finding cures for certain diseases. In addition, new coffee-growing techniques are poisoning the water locally, and eventually the world's groundwater.
         Both locally and globally, the continued spread of full-sun coffee plantations (种植园)could mean the destruction of the rainforest ecology. The loss of shade trees is already causing a slight change in the world's climate,
 and studies show that loss of oxygen-giving trees also leads to air pollution and global warming. Moreover, the new growing techniques are contributing to acidic(酸性的) soil conditions.
         It is obvious that the way much coffee is grown affects many aspects many aspects of life, from the local environment to the global ecology.
 But consumers do have a choice. They can purchase shade-grown coffee whenever possible, although at a higher cost. The future health of 
the planet and mankind is surely worth more than an inexpensive cup of coffee.