E Edwin Powell Hubble was born in 1889 in Marshfield , Missouri . He spent his early years in the state of Kentucky . Then he moved with his family to Chicago , Illinois . He attended the University of Chicago . He studied mathematics and astronomy . He was a member of the University of Chicago championship basketball team in 1909 . He was also an excellent boxer . Several people urged him to train for the world heavyweight boxing championship after college . Instead , he decided to continue his studies . He went to Queen’s College at Oxford , England . At Oxford , Hubble studied law . He was interested in British Common Law , because his family had come to America from England many years before . He spent 7 years at Oxford . In 1913 , Hubble returned to the United States . He opened a law office in Louisville , Kentucky . After a short time , however , he decided he did not want to be a lawyer . He returned to the University of Chicago . There , once again , he studied astronomy . Hubble watched the night sky with instruments at the university’s Yerkes Observatory . His research involved a major question astronomers could not answer : What are nebulae（星云）? In his research paper , Hubble said the issue could be decided only by more powerful instruments . And those instruments had not yet been developed . Soon after , Hubble bagan working with a larger and more powerful telescope at Mount Wilson . Its mirror was 250 centimeters across . It was the most powerful telescope in the world for 25 years .It had the power Hubble needed to make his major discoveries . From 1922 on , Edwin Hubble began examining more and more distant objects . His first great discovery was made when he recognized a Cepheid variable star . It was in the outer area of the great nebula called Andromeda . Cepheid variable stars are stars whose brightness changes at regular periods . Hubble’s discovery ended a long dispute . He proved wrong those who believed nebulae lay inside the Millky Way . And he proved that nebulae were galaxies themselves . Astronomers now agree that far distant galaxies do exist . 72. Why did Hubble close his law office ? A. Because it could not bring him fortune . B. Because he was tired of office work . C. Because he wanted to be devoted to astronomy . D. Because he couldn’t control himself sometimes . 73. The larger and more powerful telescope at Mount Wilson_______. A. belonged to the state of Kentucky B. was once the most powerful C. cost Hubble all his money D. was of little help to Hubble’s research 74. Which of the following statements is NOT true about Edwin Powell Hubble ? A. He studied law for three years at Oxford , England . B. He corrected people’s wrong idea about nebulae . C. He made some important discoveries at Mount Wilson . D. He showed little interest in sports while studying astronomy at college . 75. Cepheid variable stars’ brightness can be described as__________. A. changeable B. fixed C. weak D. colorful