【托福阅读题型：The Allende Meteorite句子插入题】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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　　托福阅读句子插入题：The Allende Meteorite

　　Equally perplexing constituents of Allende are the refractory inclusions: irregular white masses that tend to be larger　than chondrules. ■ They are composed of minerals uncommon on Earth, all rich in calcium, aluminum, and titanium, the　most refractory (resistant to melting) of the major elements in the nebula. ■ The same minerals that occur in refractory　inclusions are believed to be the earliest-formed substances to have condensed out of the solar nebula. ■ However,　studies of the textures of inclusions reveal that the order in which the minerals appeared in the inclusions varies from　inclusion to inclusion, and often does not match the theoretical condensation sequence for those metals. ■(The Allende Meteorite)

　　! Look at the four squares [■] that indicate where the following sentence could be added to the passage

　　It is therefore still unclear if all inclusions were formed in the same way.

　　Where would the sentence best fit?

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