Reading Comprehension of Toefl
Questions 51-60 refer to the following passage.
We believe the Earth is
about 4.6 billion years old. At present we are forced to look to other bodies
in the solar system for hints as to what the early history of the Earth was
like. Studies of our moon, Mercury, Mars, and the large satellites of Jupiter
and Saturn have provided ample evidence that all these large celestial bodies
were bombarded by smaller objects in a wide variety of sizes shortly after the
larger bodies had formed. This same bombardment must have affected Earth as
well. The lunar record indicates that the rate of impacts decreased to its
present low level about 4 billion years ago. On Earth, subsequent erosion and
crustal motions have obliterated the craters that must have formed during this
epoch.
Scientists estimate the
Earth's age by measuring the ratios of various radioactive elements in rocks.
The oldest Earth rocks tested thus far are about 3 1/3 billion years old. But no
one knows whether these are the oldest rocks on Earth. Tests on rocks from the
moon and on meteorites show that these are about 4.6 billion years old. Scientists
believe that this is the true age of the solar system and probably the true age
of the Earth.
51. In line 7, the word "obliterated" means
(A) created.
(B) destroyed.
(C) changed.
(D) eroded.
52.
According to this passage, how do scientists estimate the age of the Earth?(B) destroyed.
(C) changed.
(D) eroded.
(A)
By measuring the ratios of radioactive elements in rocks
(B) By examining fossils
(C) By studying sunspots
(D) By examining volcanic activity
53.
Scientists estimate the age of the Earth as(B) By examining fossils
(C) By studying sunspots
(D) By examining volcanic activity
(A)
3 1/3 billion years old.
(B) 4 billion years old.
(C) 4.6 billion years old.
(D) 6 billion years old.
54. Which
of the following processes led to the obliteration of the craters formed by the
bombardment of the Earth by celestial bodies?(B) 4 billion years old.
(C) 4.6 billion years old.
(D) 6 billion years old.
(A) Volcanic activity
(B) Solar radiation
(C) Gravity
(D) Crustal motions
55.
According to the passage, why are scientists forced to look at other bodies in
the solar system to determine the early history of the Earth?(B) Solar radiation
(C) Gravity
(D) Crustal motions
(A) Human alteration of
the Earth
(B) Erosion and crustal motions
(C) Solar flares
(D) Deforestation
56. What is
the BEST title for this passage?(B) Erosion and crustal motions
(C) Solar flares
(D) Deforestation
(A) "Determining
the Age of the Earth"
(B) "Determining the Age of the Solar System"
(C) "Erosion and Crustal Motion of Earth"
(D) "Radioactive Elements in Rocks"
57. Which
of the following bodies was NOT studied to give evidence that the Earth was
bombarded in its early history?(B) "Determining the Age of the Solar System"
(C) "Erosion and Crustal Motion of Earth"
(D) "Radioactive Elements in Rocks"
(A) Mars
(B) Mercury
(C) Jupiter
(D) Earth's moon
58.
Bombardment of the Earth at one time by various sized bodies is(B) Mercury
(C) Jupiter
(D) Earth's moon
(A) inferred from what
happened on other planetary bodies.
(B) documented fact.
(C) proven by the lunar record.
(D) indicated by erosion.
59. The
level of impacts of the bombardments of Earth have(B) documented fact.
(C) proven by the lunar record.
(D) indicated by erosion.
(A) decreased to below
normal.
(B) increased to a current high.
(C) increased after a periodic low.
(D) decreased to a current low.
(B) increased to a current high.
(C) increased after a periodic low.
(D) decreased to a current low.
60. In line 5, the word "bombardment" means
(A) an avoidance.
(B) an assault.
(C) an effect.
(D) a cause.
(B) an assault.
(C) an effect.
(D) a cause.
sunber:
http://education.kulichki.net/lang/toread4.html
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