第4题: [单项选择]Passage Two Questions 29 to 31 are based on the passage you have just heard.A) 2 million. C) 50,0000. B) 2.5 million. D) 15,0000. 参考答案:B 答案解析:[听力原文] How many of the children were taught at home at the beginning of 21th century according to