地处河西走廊东北部的甘肃省民勤县,石羊河流经民勤盆地(如图所示)。石羊河上游地区修建了许多水库,几乎拦截了全部河水。随着人口增长、耕地扩大,民勤县地表水骤减,地下水位急剧下降,导致植被大面积死亡。石羊河下游的民勤绿洲迅速退化,现已成为我国沙尘暴四大源地之一。据此回答下列各题。
①水资源短缺
②旱涝灾害
③土地荒漠化
④水土流失
A.①③ | B.②③ | C.①④ | D.②④ |
A.上游拦截河水,过度用水 | B.乱砍滥伐 |
C.过度放牧 | D.大量的地表径流在沙漠地区下渗 |
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同类型试题
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y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
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y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
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