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.

 

            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