【托福阅读题型：Savanna Formation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：Savanna Formation

　　【Paragraph 2】Savannas typically experience a rather prolonged dry season. One theory behind savanna　formation is that wet forest species are unable to withstand the dry season, and thus savanna, rather than rain　forest, is favored on the site. Savannas experience an annual rainfall of between 1,000 and 2,000 millimeters, most　of it falling in a five- to eight-month wet season. Though plenty of rain may fall on a savanna during the year, for　at least part of the year little does, creating the drought stress ultimately favoring grasses. Such conditions prevail　throughout much of northern South America and Cuba, but many Central American savannas as well as coastal areas of Brazil and the island of Trinidad do not fit this pattern. In these areas, rainfall per month exceeds that in　the above definition, so other factors must contribute to savanna formation.(Savanna Formation)

　　In paragraph 2, the author mentions savannas in Central America, Brazil, and the island of Trinidad in order　　to:

　　○ argue that these savannas are similar to those in South America and Cuba

　　○ point out exceptions to the pattern of savanna formation in areas with drought stress

　　○ provide additional examples of savannas in areas with five-to-eight-month wet seasons

　　○ indicate areas where savannas are being gradually replaced by rain forests

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