【托福阅读题型：Moving into Pueblos修辞目的题】托福阅读中句子插入题是重要题型之一。根据托福阅读题型不同来进行专项练习，是短期提高托福阅读能力的有效方法。同学们需要多加练习哦!

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　　托福阅读修辞目的题：Moving into Pueblos

　　【Paragraph 4】Another important push was the onset of the Little Ice Age, a climatic phenomenon that led to　cooler temperatures in the Northern Hemisphere. Although the height of the Little Ice Age was still around the corner,　some evidence suggests that temperatures were falling during the thirteenth century. The environmental changes　associated with this transition are not fully understood, but people living closest to the San Juan Mountains, to the　northeast of Mesa Verde, were affected first. Growing food at these elevations is always difficult because of the short　growing season. As the Little Ice Age progressed, farmers probably moved their fields to lower elevations, infringing on　the lands of other farmers and pushing people together, thus contributing to the aggregations. Archaeologists identify a　corresponding shift in populations toward the south and west toward Mesa Verde and away from higher elevations. (Moving into Pueblos)

　　Why does the author state that "Growing food at these elevations is always difficult because of the short growing　season"?

　　○To explain why the higher elevations were always relatively sparsely populated

　　○To suggest that any worsening of conditions would have significant consequences

　　○To emphasize how resourceful the people growing food at these elevations were

　　○To argue that farming was not the primary source of food at high elevations

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