听力原文： Sex education is a serious scientific subject, which is as important as the other sciences and arts subjects, even if it is not included in the exams, especially the college entrance examination. It shouldnt be overlooked or banned in school curriculums. Instead of being regarded as a sinful subject, it should be treated with the right attitude. In China, for thousands of years, people have felt shy and embarrassed when talking about sex, which becomes a mysterious thing in peoples view. Affected by this cultural tradition and social customs, people hold a negative attitude towards it. That is why sex education is never allowed to enter schools in an open and broad manner. As a result, few people have a correct and scientific knowledge about sex. Many teenagers know very little about sex. Driven by the forces of instinct or curiosity, they commit many crimes because of ignorance, e.g. illegal teen pregnancy, taking drugs, contracting sexual diseases. They become the innocent victims due to lack of sex education. Cant this be said to be the tragedy of our education and nation? Sex education is not new in the schools of Western countries, beginning as early as kindergarten and continuing into high school. Comprehensive sex education programmes generally cover the biology of reproduction, the psychology of relationships, and the sociology of the family. These courses leading to straight talk about a variety of subject have neither produced many negative impacts on the mental, physical and psychological development of the teenagers, nor resulted in many social troubles. It is clear that the teachers and parents cant perpetuate myths that could prevent childrens healthy sexual development. Under the proper guidance of the teachers and experts, students will grow into healthy-minded citisens and decrease the chances to see psychological doctors. Questions 23 to 25 are based on the passage you have just heard. 23. Why do Chinese people hold a negative attitude towards sex education? 24. What can we infer from the passage? 25. What is the main topic of the passage?23．