托福阅读句子插入题练习(1)

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　　例一：Extinct but already fully marine cetaceans are known from the fossil record. █ How　was the gap between a walking mammal and a swimming whale bridged? █ Missing until　recently were fossils clearly intermediate, or transitional, between land mammals and　cetaceans. █ Very exciting discoveries have finally allowed scientists to reconstruct the　most likely origins of cetaceans. █In 1979, a team looking for fossils in northern Pakistan　found what proved to be the oldest fossil whale.

　　This is a question that has puzzled scientists for ages.

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

　　This is a question that has puzzled scientists for ages.　Where would the sentence best fit?

　　例二：█ The raising of livestock is a major economic activity in semiarid lands, where grasses are generally the dominant type of natural vegetation. █The consequences of　an excessive number of livestock grazing in an area are the reduction of the vegetation cover and the trampling and pulverization of the soil. █ This is usually followed by the　drying of the soil and accelerated erosion. █

　　This economic reliance on livestock in certain regions makes large tracts of land　susceptible to overgrazing.

　　例三：█ Exhibitors, however, wanted to maximize their profits, which they could do more　readily by projecting a handful of films to hundreds of customers at a time. █ In 1895,　showmen such as Louis and Auguste Lumière perfected projection devices. █These early　projection devices were used in vaudeville theaters, local town halls, makeshift storefront　theaters, fairgrounds, and amusement parks to show films to a mass audience. █　When this widespread use of projection technology began to hurt his Kinetoscope　business, Edison acquired a projector developed by Armat and introduced it as “Edison’s　latest marvel, the Vitascope.”

　　例四：Before 1815 manufacturing in the United States had been done in homes by skilled　artisans. █ As master craftworkers, they imparted the knowledge of their trades to apprentices . █ In addition, women often worked in their homes part-time. █ After 1815　this older form of manufacturing began to give way to factories with machinery tended by　unskilled or semiskilled laborers. █ Cheap transportation networks, and the availability of　capital and credit all stimulated the shift to factory production.

　　This new form of manufacturing depended on the movement of goods to distant　locations and a centralized source of laborers.

　　例五：█Cases in which many species become extinct within a geologically short interval of　time are called mass extinctions. █There was one such event at the end of the　Cretaceous period (around 70 million years ago). █There was another, even larger, mass　extinction at the end of the Permian period (around 250 million years ago). █The Permian　event has attracted much less attention than other mass extinctions because mostly　unfamiliar species perished at that time.

　　In general, it is believed that these two extinctions resulted from drastic environmental　changes that followed meteorite impacts or massive volcanic eruptions.

　　例六： One interpretation regarding the absence of fossils during this important　100-million-year period is that early animals were soft bodied and simply did not fossilize.　█ Fossilization of soft-bodied animals is less likely than fossilization of hard-bodied animals, but it does occur. █ Conditions that promote fossilization of soft-bodied animals　include very rapid covering by sediments that create an environment that discourages　decomposition.█ In fact, fossil beds containing soft-bodied animals have been known for　many years. █

　　It is relatively rare because the fossilization of soft-bodied animals requires a special　environment.