You may think all stars look alike. By looking closely you might 1 that some seem
brighter than others. You may even notice that some appear to be slightly different in color. The
great 2 between stars and the earth makes it hard to see all the differences. The most 3
difference is brightness. The 4 of the brightness of a star as seen from the earth is known as
magnitude. The magnitude of a star 5 three things. The first is the star’s distance from the
earth. Suppose two stars are exactly alike 6 their distance from the earth. The one that is
closer will appear brighter. It will have a greater magnitude. The second thing that affects the
magnitude of a star is size. Stars differ greatly in size. There are stars that have a diameter 10 to 100
times 7 the sun. The third thing that affects the magnitude of a star is temperature. The
temperature of a star also 8 its color. 【題組】2. (A) distance (B) surface (C) frequency (D) percentage
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