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Q24 to Q27:
Years before the advent of plate
tectonics―the widely accepted theory,
developed in the mid-1960’s, the holds
Line that the major features of Earth’s surface
(5) are created by the horizontal motions
of Earth’s outer shell, or lithosphere―
a similar theory was rejected by the
geological community. In 1912, Alfred
Wegener proposed, in a widely debated
(10) theory that came to be called continental
drift, that Earth’s continents were mobile.
To most geologists today, Wegener’s
The origin of Continents and Oceans
appears an impressive and prescient
(15) document, containing several of the
essential presumptions underlying plate
tectonics theory: the horizontal mobility
of pieces of Earth’s crust; the essential
difference between oceanic and conti-
(20) nental crust; and a causal connection
between horizontal displacements and
the formation of mountain chains. Yet
despite the considerable overlap
between Wegener’s concepts and the
(25) later widely embraced plate tectonics
theory, and despite the fact that conti-
nental drift theory presented a possible
solution to the problem of the origin of
mountains at a time when existing expla-
(30) nations were seriously in doubt, in its
day Wegener’s theory was rejected
by the vast majority of geologists.
Most geologists and many historians
today believe that Wegener’s theory
(35) was rejected because of its lack of an
adequate mechanical basis. Stephen
Jay Gould, for example, argues that
continental drift theory was rejected
because it did not explain how continents
(40) could move through an apparently solid
oceanic floor. However, as Anthony
Hallam has pointed out, many scientific
phenomena, such as the ice ages, have
been accepted before they could be fully
(45) explained. The most likely cause for the
rejection of continental drift―a cause
that has been largely ignored because
we consider Wegener’s theory to have
been validated by the theory of plate
(50) tectonics―is the nature of the evidence
that was put forward to support it. Most
of Wegener’s evidence consisted of
homologies—similarities of patterns and
forms based on direct observations of
(55) rocks in the field, supported by the use
of hammers, hand lenses, and field note-
books. In contrast, the data supporting
plate tectonics were impressively
geophysical—instrumental determinations
(60) of the physical properties of Earth gar-
nered through the use of seismographs,
magnetometers, and computers.
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Q24:
The author cites Hallam (line 42) on the ice ages primarily in order to
provide an example of a geologic phenomenon whose precise causes are not fully understood by geologists today
criticize the geological community for an apparent lack of consistency in its responses to new theories
offer evidence held to undermine a common view of why Wegener’s theory was not accepted in its day
give an example of a modern scientist who believes that Wegener’s theory was rejected because it failed to adequately explain the mechanical basis of continental drift
support Gould’s rationale for why Wegener’s theory was rejected by most geologists in the early twentieth century
我认为Ｃ，标准答案Ａ
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Q25:
The author of the passage refers to the “considerable overlap” (line 23) between continental drift theory and plate tectonics theory most probably in order to
suggest that plate tectonics theory is derived from Wegener’s work
introduce a discussion comparing the elements of the two theories
examine the question of whether continental drift theory was innovative in its time
provide a reason why it might seem surprising that continental drift theory was not more widely embraced by geologists
cite an explanation that has been frequently offered for Wegener’s high standing among geologists today
我认为Ｄ，作者用ＹＥＴ，Despite,来表惊讶；标准答案Ａ
Answer: | 
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发表于 2005-1-22 14:12:00
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