托福阅读句子插入题是阅读十大题型之一，几乎在每篇文章中都会出现，但是有很多同学不能很好的解答这种题型;tpo是托福阅读备考最权威的材料，所以托福小编为大家集中整理了tpo阅读中的句子插入题，供大家参考使用。本文带来的是TPO22的内容，一起来看看吧。
TPO22-1
Spartina is an exceedingly competitive plant. ■ It spreads primarily by underground stems; colonies form when pieces of the root system or whole plants float into an area and take root or when seeds float into a suitable area and germinate. ■ Spartina establishes itself on substrates ranging from sand and silt to gravel and cobble and is tolerant of salinities ranging from that of near freshwater (0.05 percent) to that of salt water (3.5 percent). ■Because they lack oxygen, marsh sediments are high in sulfides that are toxic to most plants. ■ Spartina has the ability to take up sulfides and convert them to sulfate, a form of sulfur that the plant can use; this ability makes it easier for the grass to colonize marsh environments. Another adaptive advantage is Spartina’s ability to use carbon dioxide more efficiently than most other plants.
13.Look at the four squares [■] that indicate where the following sentence could be added to the passage.
Spartina is particularly able to tolerate high salinities because salt glands on the surface of the leaves remove the salt from the plant sap.
Where would the sentence best fit?
答案：(B)
TPO22-2
Unlike most major inventions, photography had been long and impatiently awaited. The images produced by the camera obscura, a boxlike device that used a pinhole or lens to throw an image onto a ground-glass screen or a piece of white paper, were already familiar—the device had been much employed by topographical artists like the Italian painter Canaletto in his detailed views of the city of Venice. What was lacking was a way of giving such images permanent form. This was finally achieved by Louis Daguerre (1787-1851), who perfected a way of fixing them on a silvered copper plate. His discovery, the "daguerreotype," was announced in 1839.■
A second and very different process was patented by the British inventor William Henry Talbot (1800-1877) in 1841.■ Talbot's "calotype" was the first negative-to-positive process and the direct ancestor of the modern photograph. The calotype was revolutionary in its use of chemically treated paper in which areas hit by light became dark in tone, producing a negative image.■ This "negative," as Talbot called it, could then be used to print multiple positive images on another piece of treated paper.■
13.Look at the four squares HI that indicate where the following sentence could be added to the passage
Although his process produced permanent images, each was unique and no reproduction of the picture was possible.
Where would the sentence best fit?
答案：(A)
TPO22-3
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. ■
13.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?
答案：(D)
以上就是托福阅读句子插入题(22)，大家可以在备考的时候参考复习，希望能够帮助大家的考前准备。最后前程百利祝大家都能取得理想的托福考试成绩。
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