四、閱讀測驗：
(一) Pluto was found in 1930 . It used to be the ninth planet in the solar system until the IAU changed it on August 24 , 2006.
      Many astronomers argued about whether to call Pluto a planet or not . Some thought that it was too small to be called a planet – it is even smaller than the Moon . So , at a meeting in 2006 , the astronomers decided to take Pluto off the list of planets in our solar system .
Now , there are eight planets in the solar system . But if you are a fan of Pluto, don’t worry . Astronomers sometimes change the rules . Perhaps they will change their mind at the next meeting . Who knows ?

planet 行星 solar system太陽系 IAU國際天文聯盟 astronomer天文學家
argue 爭論

【題組】

36. What is the best title for the reading ?

title 標題
(A) The Nine Planets.　　
(B) The Solar System. 　　
(C) A Planet or Not? 　　
(D) Pluto and the Moon.