Galaxies are the major building blocks of the universe. A galaxy is a giant
family of
many millions of stars, and it is held together by its own
gravitational field. Most of the
material universe is organized into galaxies of stars, together
with gas and dust.
Line There are three main types of galaxy
; spiral, elliptical, and irregular. The Milky
(5) Way is a spiral galaxy : a flattish disc of stars with two spiral
arms emerging from its
central nucleus. About one-quarter of all galaxies have this
shape. Spiral galaxies are
well supplied with the interstellar gas in which new stars form ;
as the rotating spiral
pattern sweeps around the galaxy it compresses gas and dust,
triggering the formation
of bright young stars in its arms. The elliptical galaxies have a
symmetrical elliptical or
(10) spheroidal shape with no obvious structure. Most of their member
stars are very old
and since ellipticals are devoid of interstellar gas, no new stars
are forming in them.
The biggest and brightest galaxies in the universe are ellipticals
with masses of about
1013 times that of the Sun; these giants may frequently be sources
of strong radio
emission, in which case they are called radio galaxies. About
two-thirds of all galaxies
(15) are elliptical. Irregular galaxies comprise about one-tenth of all
galaxies and they come
in many subclasses.
Measurement in space is quite
different from measurement on Earth. Some
terrestrial distances can be expressed as intervals of time : the
time to fly from one
continent to another or the time it takes to drive to work, for
example. By comparison
(20) with these familiar yardsticks, the distances to the galaxies are
incomprehensibly large,
but they too are made more manageable by using a time calibration,
in this case the
distance that light travels in one year. On such a scale the
nearest giant spiral galaxy,
the Andromeda galaxy, is two million light years away. The most
distant luminous
objects seen by telescopes are probably ten thousand million light
years away. Their
light was already halfway here before the Earth even formed. The light
from the nearby
Virgo galaxy set out when reptiles still dominated the animal
world.
Questions
40. The world "major" in line 1 is closest in meaning to
(A) intense
(B) principal
(C) huge
(D) unique
41. What does the second paragraph mainly discuss?
(A) The Milky
Way
(B) Major
categories of galaxies
(C) How elliptical galaxies are
formed
(D) Difference
between irregular and spiral galaxies
42. The word "which" in line 7 refers to
(A) dust
(B) gas
(C) pattern
(D) galaxy
43. According to the passage, new stars are formed in spiral
galaxies due to
(A) an explosion of gas
(B) the compression of gas and
dust
(C) the combining of old stars
(D) strong radio emissions
44. The word "symmetrical" in line 9 is closest in
meaning to
(A) proportionally balanced
(B) commonly seen
(C) typical large
(D) steadily growing
45. The word "obvious" in line 10 is closest in meaning
to
(A) discovered
(B) apparent
(C) understood
(D) simplistic
46. According to the passage, which of the following is NOT true
of
elliptical galaxies?
(A) They are the largest
galaxies.
(B) They mostly contain old
stars.
(C) They contain a high amount
of interstellar gas.
(D) They have a spherical shape
47. Which of the following characteristics of radio galaxies is
mentioned
in the passage?
(A) They are a type of
elliptical galaxy.
(B) They are usually too small
to be seen with a telescope
(C) They are closely related to
irregular galaxies.
(D) They are not as bright as
spiral galaxies.
48. What percentage of galaxies are irregular?
(A) 10%
(B) 25%
(C) 50%
(D) 75%
49. The word "they" in line 21 refers to
(A) intervals
(B) yardsticks
(C) distances
(D) galaxies
50. Why does the author mention the Virgo galaxy and the Andromeda
galaxy
in the third paragraph?
(A) To describe the effect that
distance has on visibility
(B) To compare the ages of two
relatively young galaxies
(C) To emphasize the vast
distances of the galaxies from Earth
(D) To explain why certain
galaxies cannot be seen by a telescope
Please tally your answer with the below provided answers and
then comment here how much you got!
Answers
40.
B 41. B 42.
B 43. B 44. A 45. B 46. C 47. A 48. A 49. C 50. C
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