Thanks to better health care, most people are living  (healthy) and longer lives. Someone who is born today can expect to live about thirty-five years longer than someone who  (be)  born in the nineteenth century. Here are five  (rule) for a healthy life.

    First. Doctors say you should get off the sofa. To keep fit, you have to walk 介词) least 10, 000 steps every day. In the past, people's jobs required more physical effort. They often (have) to walk for miles every day. When farmers were  (work) in the fields, they were keeping fit at(冠词) same time.

    Second. Rest while you can! When we were babies, we (sleep) for much of the night. Teenagers do not need as much sleep as babies, but it is important for you to get about eight  (hour) sleep a night. At weekends, you have  (get) more time, so use it not just for your friends, but for rest too.