Sports change with the seasons. People play different games in winter and summer. Swimming is fun in warm weather, but skating is good in winter.

Some sports are so interesting that people everywhere love them. Football, for example, has spread (传播) around the world. Swimming is popular in the countries near the sea or in those with many rivers. What fun it is to jump into a pool or a lake, whether in China or in Australia! And think of people in cold countries. Think how many people love to skate in Japan or in Canada.

Some sports or games go back to thousands of years ago, like running or jumping. Chinese wushu, for example, has a very long history. But basketball and volleyball are pretty new. Both are less than 150 years old. People are inventing new sports or games all the time. Waterskiing is one of the newest sports.

People from different countries may not be able to understand each other, but after a game together they often become good friends. Sports help to train a person’s character (性格). One learns to fight hard but fight fair (公平地), to win without pride (骄傲) and to lose with graces (风度).

As time goes by, sports are more and more important in life. Wherever you go, you can see different kinds of sports or games. Some sports or games can go back to thousands of years. Tai Chi, for example, is a kind of traditional Chinese physical exercise. There are also some other new sports or games. And people are keeping inventing (发明) new sports or games.

Why do people like sports? As we all know, sports can help us become strong and keep our bodies healthy. Also, they can make us clever. Different people like different kinds of sports. Some people enjoy team sports, such as basketball and football. Others like individual (个人的) sports, such as swimming and running. Skating and mountain climbing are the most popular with people who like to take part in outdoor sports.

As the seasons change, sports change too. In different seasons, people take part in different sports. For example, swimming is fun in summer, while skating or skiing is popular in winter.

Sports are important and interesting because they make our lives better and more colorful. What do you think of sports?

Most of us use alarm clocks or mobile phones to wake up at the right time for school or work. We look at our watches to know the right time for the bus or train. However, there is also a right time to eat, sleep, exercise, and take medicine. We can’t look at a clock for the right time for these activities. We must listen to the clock inside our bodies, the biological clock.

Barbara Wells exercised every morning. She woke up at 6:00 a. m. She ran about two miles before she went to work. But Barbara's legs and back started to hurt. She did some exercise before she ran. But her legs and back still hurt. She ran slower, but the pain didn’t stop. Barbara talked to her doctor. The doctor said, “Don’t run in the morning. Try to exercise later in the day. That is the time when your body is at the right temperature for exercise after work. Her legs and back didn’t hurt any more.

Today, doctors are learning more shout chronobiology(生物钟学)，the study of biological docks. They are learning about the importance of time for our bodies. For example, it is best for people to go to sleep on time every right and to eat only when they’re hungry. Also, doctors discovered that some illnesses, such as heart attacks, occur (v. 发生) most often in the morning. This information tells them that the best time to take heart medication may be at night. When patients take heart medication at night, they may prevent a heart attack in the morning.

Many doctors believe chronobiology can help us live healthier lives. It may be the right time to listen to these doctors!