1、国家公共英语（三级）笔试模拟试卷 225及答案与解析 Part A Directions: Read the following three texts. Answer the questions on each text by choosing A, B, C or D. Mark your answers on ANSWER SHEET 1. 0 Standing on the rim of the Grand Canyon(大峡谷 )， gazing across this giant would in the Earths surface, a visitor might assume
2、 that the canyon had been caused by some ancient convulsing (震动 ). In fact, the events that produced the canyon, far from being sudden and catastrophic, simply add up to the slow and orderly process of erosion. Many millions of years ago, the Colorado Plateau in the Grand Canyon area contained 1000
3、more feet of rock than it does today and was relatively level. The additional material consisted of some 14 layered formations of rock. In the Grand Canyon region these layers were largely worn away over the course of millions of years. Approximately 65 million years ago the plateaus flat surface in
4、 the Grand Canyon area bulged upward from internal pressure, geologists refer to this bulging actions upwading(弯 曲上升 ); it was followed by a general elevation of the whole Colorado Plateau, a process that is still going on. As the plateau gradually rose, shallow rivers that winded across it began to
5、 run more swiftly and cut more definite courses. One of these rivers, located east of the upward, was the ancestor of the Colorado. Another river system, called the Hualapai, flowing west of the upward, extended itself eastward by cutting back into the upward, it eventually connected with the ancien
6、t Colorado and captured its waters. The new river then began to carve out the 277-mile-long trench that eventually became the Grand Canyon. Geologists estimate that this initial cutting action began no earlier than 10 million years ago. Since then, the Canyon forming has been cumulative. To the corr
7、osive force of the river itself have been added other factors. Heat and cold, rain and snow, along with the varying resistance of the rocks, increase the opportunities for erosions. the Canyon walls crumble, the river acquires a cutting tool. Tons of debris, rainfall running off the high plateau cre
8、ates feeder streams that carve side canyons. Pushing slowly backward into the plateau, the side canyons expose new rocks, and the pattern of erosion continues. 1 The passage mainly discusses_. （ A） patterns of erosion in different mountain ranges （ B） forces that made the Grand Canyon （ C） the incre
9、asing pollution of the Colorado River （ D） the sudden appearance of the Grand Canyon 2 The word“wound“(Line 2, Para. 1)indicates that_. （ A） it was caused by some ancient convulsion （ B） its presence is an embarrassment to the state of Colorado （ C） it looks like an injury on the Earths surface （ D）
10、 it has caused many visitors to injure themselves 3 According to the passage how many miles long was the trench that became known as the Grand Canyon? （ A） 10 100. （ B） 277. （ C） 14. （ D） 10. 4 It can be concluded from this passage about the Grand Canyon that_. （ A） its shapes are constantly changin
11、g （ B） it contains approximately 14 million tons of rock （ C） its eruptions have increased in recent years （ D） it is being eroded by toxic waste and pollutants 5 The passage would most likely be found in a texbook on which of the following subjects? （ A） Astronomy. （ B） Botany(植物学 ). （ C） Geology.
12、（ D） Chemistry. 国家公共英语（三级）笔试模拟试卷 225答案与解析 Part A Directions: Read the following three texts. Answer the questions on each text by choosing A, B, C or D. Mark your answers on ANSWER SHEET 1. 1 【正确答案】 B 【试题解析】 第一段指出大峡谷的形成是由于缓慢有序的侵蚀形成的；第二段又说几百万年前大峡谷一带还是平面 的，后来被逐渐侵蚀；第三段说由于地面降起，便有了高原河流，也有了著名的大峡谷；最后一段又进一步
13、说明了大峡谷的进一步形成是由于力的作用。因而本篇讨论的是形成大峡谷的各种力。故选 B。 2 【正确答案】 C 【试题解析】 本章开始说 “站在大峡谷的边缘，放眼望着地球表面上的巨大豁口，游客可能认为峡谷是由于古代地动形成的。 ”可见作者在这里将大峡谷暗喻成伤口。故选 C。 3 【正确答案】 B 【试题解析】 第三段倒数第二句话说 “然后，新的河流开始切割出最后成为大峡谷的长达 277英里的壕沟来 ”， 因而本篇作者认为大峡谷长 227英里，故选 B。 4 【正确答案】 A 【试题解析】 最后一段 “从那以后，大峡谷的形成日积月累，除了河流的侵蚀作用外，还有其他因素，如冷热、雨雪以及岩石的各种阻力增加了侵蚀的可能性。大峡谷壁面塌落，河流获得了切割工具。成吨的碎石和从高原上流下的雨水产生的支流切割峡谷壁，又逐步侵蚀到高原，峡谷边暴露出新的岩石，而侵蚀仍在继续 ”。可见应选 A。 5 【正确答案】 C 【试题解析】 从文章内容上可以看出本篇不是天文学、植物学，也不是化学，而是地质学方面的内容。 因而选 C。
