托福閱讀真題 Desert formation 解答(7)
The sentence provided, “This economic reliance on live stock in certain regions makes large tracts of land susceptible to overgrazing,” is best inserted at Square 2. The inserted sentence refers explicitly to relying on “livestock in certain regions.” Those regions are the ones described in the sentence preceding square2, which states that raising livestock is “a major economic activity in semiarid lands.” The inserted sentence then explains that this reliance “makes large tracts of land susceptible to overgrazing.” The sentence that follows square 2 goes on to say that “The consequences of an excessive number of livestock grazing in an area are… ” Thus, the inserted sentence contains references to both the sentence before square 2 and the sentence after square 2. This is not true of any of the other possible insert points, so square 2 is correct.
