题目

The writer Margaret Mitchell is best known for writing Gone with the Wind, first published in 1936. Her book and the movie based on it, tell a story of love and survival during the American Civil War. Visitors to the Margaret Mitchell House in Atlanta, Georgia, can go where she lived when she started composing the story and learn more about her life. Our first stop at the Margaret Mitchell House is an exhibit area telling about the writer’s life. She was born in Atlanta in 1900. She started writing stories when she was a child. She started working as a reporter for the Atlanta Journal某非金属单质A和氧气发生化合反应生成B。B为气体，其体积是反应掉氧气体积的两倍(同温、同压)。以下对B的分子组成的推测一定正确的是( )A. 有1个氧原子 B. 有2个氧原子C. 有1个A原子 D. 有2个A原子