托福(阅读)历年真题试卷汇编4(题后含答案及解析)

托福（阅读）历年真题试卷汇编4 (题后含答案及解析)

题型有： 3. Reading Comprehension

Sections Three：Reading Comprehension

Early Theories of Continental DriftP1: The idea that the geography of Earth was

different in the past than it is today is not new. As far back as 1620, Francis Bacon

spotted that the west coast of Africa and the east coast of South America looked as if

they would fit together, like pieces of a jigsaw puzzle. Between then and 1912, other

people identified further similarities between other continental coastlines. But because

much of the early support for mobilism was based on far-flung intercontinental

similarities, geologists tended to be skeptical of the fieldwork of others.P2: During the

late nineteenth century, Austrian geologist Eduard Suess proposed the name

“Gondwanaland” in his book The Face of the Earth (1885) and gave far greater

emphasis to the evolutionary nature of the earth and he noted the similarities among

the Late Paleozoic plant fossils of India, Australia, South Africa, and South America.

Based upon glossopteris fern fossils in such regions, he explained that the three land

masses were once connected in a supercontinent which he names Gondwanaland, and

that the ocean flooded the spaces currently between those lands. Thus, in his view, the

similarities of fossils on these continents could be accounted for by postulating the

concept of a land bridge that existed once but subsided later.P3: Later, a number of

refinements to Suess’s theory were made. The American geologist Frank Taylor

published a pamphlet in 1910 presenting his concept of “horizontal displacement”. He

explained the formation of mountain ranges as a result of the lateral movements of

continents. With the earth’s capture of the moon, the gravitational forces between

them generated a pull towards lower latitudes where they thickened and formed

folded mountain belts especially in middle latitudes. Although we now know that

Taylor’s explanation of continental drift is erroneous, one of his most significant

contributions was his suggestion that the Mid-Atlantic Ridge— an underwater

mountain range discovered by the 1872-1876 British HMS Challenger expeditions—might mark the site at which an ancient continent broke apart, forming the present-day

Atlantic Ocean.P4: However, it is Alfred Wegener, a German meteorologist, who is

generally credited with developing the hypothesis of continental drift. In his

monumental book, The Origin of Continents and Oceans (1915), Wegener theorized

that a single supercontinent he called “Pangaea” existed sometime between 350

million to 225 million years ago. Wegner portrayed his grand concept of continental

movement in a series of maps showing the breakup of Pangaea and the movement of

various continents to their present-day locations. What evidence did Wegener use to

support his hypothesis of continental drift? First, Wegener noted that there is

geographical similarity along both the coasts of the Atlantic Ocean. The opposing

coasts of the Atlantic can be fitted together in the same way as two cut off pieces of

wood can be refitted. Furthermore, mountain ranges and glacial deposits seem to

match up in such a way that suggests continents could have once been a single

landmass. Finally, many of the same fossils and vegetative remains are found today

on widely separated continents, indicating that the continents must have been in

proximity at one time. During his days, Wegener was regarded as an advocate rather

than as an impartial scientific observer, appearing to ignore vast evidence unfavorable

to his ideas and distort other evidence to bring it into harmony with the theory.P5:

After Wegener’s death, a South African geologist Alexander Du Toit continued to

assemble fossil evidence for Pangaea. He noted that fossils of the now extinct reptile

“Mesosaurus” occur in rocks of the same age in both Brazil and South Africa.

Because the physiology of freshwater and marine animals is completely different, it is

hard to imagine how a freshwater reptile could have swum across the Atlantic Ocean

and then found a freshwater environment nearly identical to its former habitat.

Moreover, if Mesosaurus could have swum across the ocean, its fossil remains should

be widely dispersed. It is more logical to assume that Mesosaurus lived in lakes in

what were once adjacent areas of South America and Africa when it was united into a

single continent. Notwithstanding all of the empirical evidence in favor of continental

drift theory presented here, most geologists at the time refused to entertain the

idea.P6 :The debate over continental drift has the same role and stature in the history

of the earth sciences as the debate over Darwinian evolution in the history of life

sciences and the debates over relativity and quantum theory in the history of physics.