[問題] TTGWD2-Q6~9

[dibert8]

TTGWD2-Q6 to Q9:
Scientists generally credit
violent collisions between
tectonic plates, the mobile
Line fragments of Earth’s rocky
(5) outer shell, with sculpting
the planet’s surface, as, for
example, when what is now
the Indian subcontinent col-
lided with Asia, producing
(10) the Himalayan Mountains.
However, plate tectonics
cannot fully explain certain
massive surface features,
such as the “superswell”
(15) of southern Africa, a vast
plateau over 1,000 miles
across and nearly a mile
high. Geologic evidence
shows that southern African
(20) has been slowly rising for
the past 100 million years,
yet it has not experienced
a tectonic collision for
nearly 400 million years.
(25) The explanation may be in
Earth’s mantle, the layer of
rock underlying the tectonic
plates and extending down
over 1,800 miles to the outer
(30) edge of Earth’s iron core.

Since the early twentieth
century, geophysicists have
understood that the mantle
churns and roils like a thick
(35) soup. The relative low
density of the hottest rock
makes that material buoyant,
so it slowly ascends, while
cooler, denser rock sinks
(40) until heat escaping the mol-
ten core warms it enough to
make it rise again. While
this process of convection
was known to enable the
(45) horizontal movement of tec-
tonic plates, until recently
geophysicists were skeptical
of its ability to lift or lower the
planet’s surface vertically.
(50) However, recent technolog-
ical advances have allowed
geophysicists to make three-
dimensional “snapshots”
of the mantle by measuring
(55) vibrations, or seismic waves,
set in motion by earthquakes
originating in the planet’s
outer shell and recording
the time it takes for them to
(60) travel from an earthquake’s
epicenter to a particular
recording station at the
surface. Because geo-
physicists know that seismic
(65) waves become sluggish in
hot, low-density rock, and
speed up in colder, denser
regions, they can now infer
the temperatures and den-
(70) sities in a given segment of
the interior. By compiling
a map of seismic velocities
from thousands of earth-
quakes across the globe,
(75) they can also begin to map
temperatures and densities
throughout the mantle. These
methods have revealed some
unexpectedly immense for-
(80) mations in the deepest parts
of the mantle; the largest
of these is a buoyant mass
of hot rock directly below
Africa’s southern tip. Dis-
(85) pelling researchers’ initial
doubts, computer models
have confirmed that this
formation is buoyant enough
to rise slowly within the mantle
(90) and strong enough to push
Africa upward as it rises.

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Q23:
The passage is primarily concerned with

A. describing a traditional explanation for the vertical movement of Earth’s surface
B. discussing recent geophysical research that may explain certain features of Earth’s surface that were previously difficult to account for
C. combining elements of several theories in order to develop a plausible explanation for a poorly understood feature of Earth’s surface
D. providing new evidence in support of a long-standing belief about how certain of Earth’s massive surface features were created
E. questioning the implications of geophysicists’ recent findings regarding the composition and density of Earth’s mantle
--------------------------------------------------------------------------------
Q24:
The passage suggests that geophysicists can now infer the characteristics in a given segment of the mantle by doing which of the following?

A. Observing how long it takes for seismic waves to travel from an earthquake’s epicenter to a particular surface location and applying knowledge of how rock temperature and density affect the velocity of those waves
B. Analyzing the results of studies linking the formation of some of Earth’s surface features with the violent collisions of tectonic plates and inferring the causes of the information of other features from those results
C. Recording data about earthquakes throughout the world and correlating the relative force and duration of those earthquakes with information about their geological environment
D. Comparing data about earthquakes that occur in southern Africa’s superswell with data about other types of seismic events that occur there
E. Using computer models to estimate the length of time it would take for a hypothetical landmass 1,000 miles across to rise one mile vertically
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Q25:
In line 10, the author mentions the Himalayan Mountains most likely in order to

A. highlight certain similarities between the southern African superswell and other massive features on Earth’s surface
B. identify a feature of Earth’s surface that predates the origins of the southern African superswell
C. provide an example of a feature of Earth’s surface that can explained by plate tectonics
D. suggest that geophysicists are correct in attributing the sculpting of Earth’s surface to violent collisions between tectonic plates
E. give an example of a feature of Earth’s surface that scientists are unable to explain fully
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Q26:
According to the passage, the computer models referred to in line 86 have had which of the following effects?

A. They have confirmed researchers’ doubts regarding the theory that convection within the mantle can lift or lower Earth’s surface vertically.
B. They have cast doubt on the validity of plate-tectonics theory as an explanation for the sculpting of Earth’s mountain ranges.
C. They have proved geophysicists’ theory that the behavior of seismic waves in Earth’s mantle is related to the temperature of the rock through which they are traveling.
D. They have convinced formerly skeptical researchers that rock formations deep in Earth’s mantle below southern Africa could have created the superswell.
E. They have confirmed researchers’ speculation that masses of hot rock are buoyant enough to rise to the upper part of Earth’s mantle.



Ans : BACD

討論 Q26 ,細節題
computer models 從 line 50 開始到結束
(D) 似乎跳太遠了 (superswell 在 line 14); 文章裡也沒有 skeptical researchers
覺得 (E) 比較好.
line 46~49
until recently
geophysicists were skeptical
of its ability to lift or lower the
planet’s surface vertically.
最後,
computer models
have confirmed that this
formation is buoyant enough
to rise slowly within the mantle
(90) and strong enough to push
Africa upward as it rises.
rise = lift

[hwatai]

小弟選(A)

46~49行是一個skeptism(可以水平運動，但是可以垂直運動嗎？)，也就是(A)　 (48行的its = 43行的process of conviction = A選項用字)

然後50行立刻出現however，表示轉折，表示新科技可以解決skeptism

(E)的句意表示skeptism的中心在buoyant enough與否，好像不對；
疑點應該不在"到底要多麼地buouyant~？"，而是"垂直運動"的可行性

而最後一句話
computer models have confirmed that this formation is buoyant enough to rise slowly within the mantle and strong enough to push Africa upward as it rises.
也呼應了垂直運動被confirm可行

請大家討論看看

[dibert8]

While
this process of convection
was known to enable the
(45) horizontal movement of tec-
tonic plates, until recently
geophysicists were skeptical
of its ability to lift or lower the
planet’s surface vertically.

convection 是已知,應該不用再澄清.
skeptical of its ability 說明的確不知"到底要多麼地buouyant~？"才能使地殼上升.

不過 (E) 的內容好像真的不對: researchers 並沒有推測 (i.e. speculation) 熱石的浮力足以稱起地殼,反之,他們懷疑浮力夠不夠大.

Dis-
(85) pelling researchers’ initial
doubts, computer models
have confirmed that this
formation is buoyant enough
to rise slowly within the mantle
(90) and strong enough to push
Africa upward as it rises.
formation = superswell 這樣是不是就 (D) 囉?

[小花]

Dis-
(85) pelling researchers’ initial
doubts, computer models
have confirmed that this
formation is buoyant enough
to rise slowly within the mantle
(90) and strong enough to push
Africa upward as it rises.
我查了Collins對dispel的解釋是
dispel

To dispel an idea or feeling that people have means to stop them having it.

從句子結構看
computer models證實了科學家的懷疑是錯的

所以AE 應該不是答案
支持科學家懷疑的立場
A. They have confirmed researchers’ doubts regarding the theory that convection within the mantle can lift or lower Earth’s surface vertically

E. They have confirmed researchers’ speculation that masses of hot rock are buoyant enough to rise to the upper part of Earth’s mantle.

個人淺見
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