元素不能循环使生态系统运转失灵的直接后果是(  )

元素不能循环使生态系统运转失灵的直接后果是(  ) A.疏松的土壤在冬春季被风吹走 B.草地的生长一年不如一年 C.草地的压力急剧加大,超过了极限 D.氮素严重

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混凝土结构的缺点有(  )。

混凝土结构的缺点有(  )。 A.施工复杂 B.抗裂性较差 C.自重大 D.工期较长 E.稳定性差

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The word "vision" ( Paragraph 2 ) refers to the sense of

The word "vision" ( Paragraph 2 ) refers to the sense ofA.taste B.touch C.heari

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What made Alex say "There are good people everywhere in thi

What made Alex say "There are good people everywhere in this world"?A.Some stra

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What do we know about Alex from the text?

What do we know about Alex from the text?A.He and his wife worked in the U. S.

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