【备考必备】托福官方真题Official8阅读长难句资料汇总

在这里小编为大家带来托福官方真题Official8阅读长难句，希望对大家提高托福阅读水平有所帮助!

托福官方真题Official8阅读长难句官方真题Official8: The Rise of Teotihuacan

1. Among the main factors are Teotihuacán’s geographic location on a natural trade route　to the south and east of the Valley of Mexico, the obsidian resources in the Teotihuacán　Valley itself, and the valley’s potential for extensive irrigation.

2. The exact role of other factors is much more difficult to pinpoint―for instance,　Teotihuacán’s religious significance as a shrine, the historical situation in and around the　Valley of Mexico toward the end of the first millennium B.C., the ingenuity and　foresightedness of Teotihuacán’s elite, and, finally, the impact of natural disasters, such　as the volcanic eruptions of the late first millennium B.C.

3. The hard volcanic stone was a resource that had been in great demand for many years,　at least since the rise of the Olmecs (a people who flourished between 1200 and 400 B.C.),　and it apparently had a secure market.

官方真题Official8: Extinction of the Dinosaurs

1. Critics also point out that the shallow seaways had retreated from and advanced on the　continents numerous times during the Mesozoic, so why did the dinosaurs survive theclimatic changes associated with the earlier fluctuations but not with this one?

2. Scientists felt that they could get an idea of how long the extinctions took by　determining how long it took to deposit this one centimeter of clay and they thought they　could determine the time it took to deposit the clay by determining the amount of the　element iridium (Ir) it contained.

3. Their calculations show that the impact kicked up a dust cloud that cut off sunlight forseveral months, inhibiting photosynthesis in plants; decreased surface temperatures on　continents to below freezing; caused extreme episodes of acid rain; and significantly　raised long-term global temperatures through the greenhouse effect.

托福官方真题Official8阅读长难句官方真题Official8: Running water on Mars

1. The onrushing water arising from these flash floods likely also formed the oddteardrop-shaped “islands” (resembling the miniature versions seen in the wet sand of our　beaches at low tide) that have been found on the plains close to the ends of the outflow　channels.

2. Judging from the width and depth of the channels, the flow rates must have been truly　enormous—perhaps as much as a hundred times greater than the 105 tons per second　carried by the great Amazon river.

3. A 2003 Mars Global Surveyor image shows what mission specialists think may be a　delta—a fan-shaped network of channels and sediments where a river once flowed into a　larger body of water, in this case a lake filling a crater in the southern highlands.

4. But detractors maintain that the terraces could also have been created by geological　activity, perhaps related to the geologic forces that depressed the Northern Hemisphere　far below the level of the south, in which case they have nothing whatever to do with　Martian water.

5. Furthermore, Mars Global Surveyor data released in 2003 seem to indicate that the　Martian surface contains too few carbonate rock layers—layers containing compounds ofcarbon and oxygen—that should have been formed in abundance in an ancient ocean.

6. Aside from some small-scale gullies (channels) found since 2000, which are　inconclusive, astronomers have no direct evidence for liquid water anywhere on the　surface of Mars today, and the amount of water vapor in the Martian atmosphere is tiny.

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