Questions 4 to 6 are based on the following passage. At the end of the passage, you will be given 15 seconds to answer the questions.
Now，listen to the passage.
4. According to the passage, the focus of young college students, concerns about health is mainly on _____.
A. their present health condition.
B. their future health.
C. how to take care of themselves after retirement.
D. how long they are going to live.
5. The following ways can help you improve health EXCEPT_____.
A. doing strength training with weights
B. eating better food
C. doing exercise
D. enjoying rational diet
6. According to the passage，we can conclude that_____.
A. modem man is more intelligent than their ancestors
B. children are vulnerable to diseases
C. modem man can avoid some health problems which troubled their ancestors
D. keeping healthy is very difficult