Thanks to better health care， most people are living healthier and longer lives． Someone who is born today can expect to live about thirty﹣five years longer than someone who was born in the nineteenth century． It is even thought that in the future more and more people will celebrate their hundredth birthdays． Here are some rules for a health life．

Get off the sofa!

Sure， it is comfortable to sit on the sofa and watch TV． But doctors say you should get off the sofa． To keep fit， you have to walk at least 10000steps every day． In the past， people's jobs required more physical effort． They often had to walk for miles every day． When farmers were working in the fields， they were keeping fit at the same time． Think about it： Do you get the same amount of exercise today as they did in the past？

Eat healthy food!

It is important to eat food that is fresh and natural， for example， fruit and vegetables． Fast food is not healthy． You should only have itonce in a while． Eating too much of the wrong food will harm your health．

Rest while you can!

When we were babies， we slept for much of the night． Teenagers do not need as much sleep as babies， but it is important for you to get about eight hours' sleep a night． At weekends， you have got more time， so use it not just for your friends， but for rest too．

Do not worry， be happy!

Many people believe that happiness is important for our general health． Sometimes it is not easy to be a teenager because of the difficulties of school， exams or friendships． If you are worried about something， talk to your parents or your teacher．

29． In the passage， "Get off the sofa!" means 　　．

A．	We should take some exercise
B．	We shouldn't watch TV on the sofa
C．	We should get off the sofa to keep fit
D．	We shouldn't stay at home for a long time

30． The underlined word "it" in the passage refers to （指代） 　　．

A．	healthy food
B．	fast food
C．	natural food
D．	fresh food

31． According to the passage， which of the following is TRUE？ 　　

A．	The best rest is to spend more time with friends．
B．	It is necessary for teenagers to get enough sleep．
C．	Teenagers also need as much sleep as babies at night．
D．	Sleeping for much of the night will do harm to your health．

32． The passage is mainly about 　　．

A．	how to be a happy teenager
B．	the importance of a healthy life
C．	the ways of leading a healthy life
D．	teenagers' common healthy problems