0308 reading 27

dhxy

呵呵，谢谢大家！

The wide variety of climates in North America has helped spawn a complex pattern of

    soil regions. In general, the realm’s soils also reflect the broad environmental partitioning

    into “humid America” and “arid America.” Where annual precipitation exceeds 20 inches

(50 centimeters),soils in humid areas tend to be acidic in chemical content, Since crops

(5 ) do best in soils that are neither acidic(higher in acid content) nor alkaline(higher in salt content).fertilization is necessary to achieve the desired level of neutrality between the

    two. Arid America’s soils are typically alkaline and must be fertilized back toward

    neutrality by adding acidic compounds. Although many of these dryland soils, particularly

    in the Great Plains, are quite fertile, European settlers learned over a century ago that

(10) water is the main missing ingredient in achieving their agricultural potential. In the

1970’s, certain irrigation methods were perfected and finally provided a real opportunity

    to expand more intensive farming west from the Central Lowland into the drier portions

    of the Great Plains. Glaciation also enhanced the rich legacy of fertile soils in the central

    United States,both from the deposition of mineral-rich glacial debris left by meltwater

(15) and from thick layers of fine wind-blown glacial material, called loess, in and around the

    middle Mississippi Valley.

       Natural vegetation patterns could be displayed on a map of North America, but the

    enormous human modification of the North American environment in modern times has

    all but reduced this regionalization scheme to the level of the hypothetical. Nonetheless,

(20) the humid America-arid America dichotomy is still a valid generalization: the natural

vegetation of areas receiving more than 20 inches of water yearly is forest, whereas the

    drier climates give rise to a grassland cover. The forests of North America tent to make

    a broad transition by latitude. In the Canadian North, needle-leaf forests dominate, but

these coniferous trees become mixed with broadleaf deciduous trees as one crosses the

(25) border into the Northeast United States. As one proceeds toward the Southeast, broadleaf vegetation becomes dominant. Arid America mostly consists of short-grass prairies or

    stepper. The only areas of true desert are in the Southwest.

27 The phrase “this regionalization scheme” in line 19 refers to the

(A) movements of glacial deposits

(B)  patterns of natural vegetation

(C) human modification of the North American environment

(D) distinction between humid America and arid America

zhoushao

以下是引用dhxy在2004-11-13 11:27:00的发言：

呵呵，谢谢大家！

The wide variety of climates in North America has helped spawn a complex pattern of

    soil regions. In general, the realm’s soils also reflect the broad environmental partitioning

    into “humid America” and “arid America.” Where annual precipitation exceeds 20 inches

(50 centimeters),soils in humid areas tend to be acidic in chemical content, Since crops

(5 ) do best in soils that are neither acidic(higher in acid content) nor alkaline(higher in salt content).fertilization is necessary to achieve the desired level of neutrality between the

    two. Arid America’s soils are typically alkaline and must be fertilized back toward

    neutrality by adding acidic compounds. Although many of these dryland soils, particularly

    in the Great Plains, are quite fertile, European settlers learned over a century ago that

(10) water is the main missing ingredient in achieving their agricultural potential. In the

1970’s, certain irrigation methods were perfected and finally provided a real opportunity

    to expand more intensive farming west from the Central Lowland into the drier portions

    of the Great Plains. Glaciation also enhanced the rich legacy of fertile soils in the central

    United States,both from the deposition of mineral-rich glacial debris left by meltwater

(15) and from thick layers of fine wind-blown glacial material, called loess, in and around the

    middle Mississippi Valley.

       Natural vegetation patterns could be displayed on a map of North America, but the

    enormous human modification of the North American environment in modern times has

    all but reduced this regionalization scheme to the level of the hypothetical. Nonetheless,

(20) the humid America-arid America dichotomy is still a valid generalization: the natural

vegetation of areas receiving more than 20 inches of water yearly is forest, whereas the

    drier climates give rise to a grassland cover. The forests of North America tent to make

    a broad transition by latitude. In the Canadian North, needle-leaf forests dominate, but

these coniferous trees become mixed with broadleaf deciduous trees as one crosses the

(25) border into the Northeast United States. As one proceeds toward the Southeast, broadleaf vegetation becomes dominant. Arid America mostly consists of short-grass prairies or

    stepper. The only areas of true desert are in the Southwest.

27 The phrase “this regionalization scheme” in line 19 refers to the

(A) movements of glacial deposits

(B)  patterns of natural vegetation

(C) human modification of the North American environment

(D) distinction between humid America and arid America

MM，这到题单靠作题的技巧还是有难度找出答案，需要对全文又一个意思上大致的了解，从this regionalization scheme知肯定是有所指，大致是地区划分的意思，再看看前后，一般看前，但是好像不合适，就往后看，后面偶画线的就是一个提示了。所以选D。

dhxy

姐姐分析得极是，但是我选的是B，还是有点不明白错在哪里啊，我的阅读真是差劲！

zhoushao

MM,B很迷惑的，开始偶在这个选项上也蒙了一下，因为和原文的词很一致，但是patterns of natural vegetation问的是植物生长的类型，而题中给的是区域化，regionalization scheme，MM好好体会一下

dhxy

呵呵，终于全明白了！

promising

这个题目应该是B. 可以把答案改过来么？

eross

答案是D