We should start thinking about how to improve our lifestyle when we are younger. Here are three simple habits to be healthier.

Take care of your teeth

It may sound surprising, but there is a connection between brushing teeth and health.

Wondering if you’re brushing enough? A Scottish study found that people who brushed their teeth twice a day had a lower heart attack (侵袭) risk than those who only brushed once a day.

Stay active

Telomeres (端粒) are a part of people’s DNA. They are getting shorter and shorter as you age. People with high physical activity levels have telomeres that are nine years “younger” than those who are so-called couch potatoes. High physical activity levels mean 30 minutes of exercise every day increased life length by three years.

Get good sleep

Sleep is like a “cleaning” for your brain. But not sleeping too much is also important. Getting less than seven or eight hours of sleep can cause an increased chance of death, but sleeping more than 11 hours a night is related to an even larger increase.

Try to keep some habits that help you sleep better, such as having a fixed bedtime and removing electronics from the bedroom.

Every Saturday evening, many people come to an open square in a small town in Xi’an. They want to watch Chen Kun and his friends put on a shadow puppet play（皮影戏）.

Shadow puppets are made of hard leather（皮革）. The leather is cut out in the shape (A) ________ a person.

During a shadow puppet play, Chen stands behind a white screen with lights behind (B) it. The audience sit in front of the screen. Chen and his friends hold the puppets very close (C) ________ the screen so the audience can see the puppets’ shadows clearly. Then they move the puppets around and do the voices of the different characters.

Shadow puppet plays are a traditional Chinese art. (D) Nowadays, shadow puppet plays are not as popular as before. To let more young people learn the skills of shadow puppet plays, Chen provides students with training courses. (E) Shadow puppet plays are quite a hard job, but he still wants to pass this traditional art down.

For most students，the time of exams is very stressful and difficult. Some students find the exam time is so bad that they become ill，because they are afraid of failing，and they are afraid of letting their parents down. If exams are really making you ill or worried，don't hide your feelings. Talk to someone about it. If he or she doesn't help you，ask someone else.

Here are some top tips given by educational psychologists（教育心理学家）.

•Ask a teacher about how to revise and about exam skills-how to work when you are in an exam.

•Take a short rest during your time of work and revision. If your mind is tired，it will not remember well.

•Revise at the time when you know you will work at your best.

•Get enough sleep，and eat healthy food.

•If you feel bad，talk to someone about your worries. But don't be too relaxed！Some stress over exams makes you work hard for them.

•If it upsets you to talk to your friends about an exam when it is finished，don't do it！In fact，don't even think about the exam you have finished. What is done has been done. You cannot change what you have written！

•If you are studying in the evening，don't go straight to bed afterwards（之后）.Your mind will still be "going round and round"─thinking too much. Choose something that will relax you，and make you think of other things.