Most of us use alarm clocks to wake up at the right time for school or we look at our watches to know the right time for the bus or train. However, there is also a “clock” inside our bodies — the biological（生物的）clock — to tell us when to eat, sleep, exercise, and even take medicine. The latest finding shows that we must listen to it.

Eva Green exercised every morning. She woke up at 6:00 am and ran about two miles before she went to work. But Eva’s legs and back started to hurt. So she did some exercise before running. She tried to run slowly, but the pain didn’t stop. Eva talked to her doctor. The doctor said, “Don’t run in the morning. Exercise later in the day. That is the time when your body is at the right temperature for exercise.” She did as the doctor said, and her legs and back didn’t hurt anymore.

Today, doctors are learning more about the biological clock. They are learning about the importance of time to our bodies. For example, it is best for people to go to sleep on time every night and to eat only when they’re hungry. Also, doctors discover that some illnesses, such as heart attacks, happen most often in the morning. This information tells them that the best time to take heart medicine may be at night. When a patient takes medicine at night, it may prevent a heart attack in the morning.

Many doctors believe chronobiology（生物钟学）can help us live a healthier life. It may be the right time to listen to these doctors!

Men sometimes say, “We are better and cleverer than women. Women never invent things. We do.” It is true that men have invented a lot of useful things: the alphabet, machines, rockets, and guns, too. But scientists and archeologists (考古学家) now agree that (农业). Before the inventing of agriculture, men were hunters. They went out every day. Sometimes they killed animals, sometimes animals killed them. Life was difficult and dangerous. Women had to go out every day, too. They collected roots, fruit and grasses. Then, one day, more than 10,000 years ago, a woman dropped some grass seeds. She dropped them near her home in the Middle East. They grew, and the first wheat was born. The idea grew, too. Women planted roots and fruit trees. Then they could stay at home and look after the children and the animals. Women liked baby animals. Archeologists think that women kept the first domestic animals: dogs, cows, sheep, and goats. That idea grew, too. Then their husbands did not have to go hunting for meat. They stayed at home. They built villages and cities. Civilization (文明) began. Men began civilization after women invented agriculture.

Do you know why different animals or pests (昆虫) have their special color? Colors in them seem to be used mainly to protect themselves.

Some birds like eating locusts (蝗虫), but birds can’t easily catch them. Why? Because locusts change their colors with the change of the colors of crop. When crops are green, locusts look green. But as the harvest time comes, locusts change to the same brown color as crops have. Some other pests with different colors from plants are easily found. So they have to hide themselves for lives and appear only at night.

If you study the animal life, you’ll find the main use of coloring is to protect themselves. Bears, lions, and other animals move quietly through forests. They can’t be easily seen by hunters, because they have the colors much like the trees.

Have you ever noticed an even stranger act? A kind of fish in the sea can send out a kind of very black liquid (液体) when in danger. While the liquid spreads over, its enemies can’t find it. And it immediately swims away. So it has lived up now though it is not strong at all.

The 24th Beijing Winter Olympics will begin on 4th February, 2022. The Winter Paralympics will begin a month later. Let’s meet the mascots!

I’m Bing Dwen Dwen. I’m the mascot(吉祥物) of the 2022 Winter Olympics. I am a black and white panda wearing a full-body “shell” made of ice. The red heart shape in my left palm(手心) means welcoming the friends from other countries. The bright colors of the circle around my face stand for ice and snow sport tracks, meaning connectivity and advanced technologies. I look like an astronaut(宇航员), making full use of new technologies for a future with all kinds of possibilities.

Shuey Rhon Rhon is here! I’m the mascot of the 2022 Winter Paralympics(残疾人运动会). What do you think of when you see me? Does a red lantern(灯笼) come into your mind? That’s what I look like. Take a look at my head. There are paper cutting of doves(和平鸽). They make up a circle. Follow me. I’ll light the way to the Paralympics.