Hello, everyone!  1 to Class 3. I'm your new English teacher, Mr. Yang. Now let me tell you our class  2. First, you can't be late 3 class. You must 4 on time. Second, you must bring your English books and notebooks to every 5. Third, you must   6 English during the pair work activities. If it's 7 for you, you can ask me for help. Fourth, if you have any  8, you must put up your hands(举手). You can't talk or stand up without permission（未经许可）. These are all the rules. They are good for you,  9 you must follow them. I hope we can have a good 10 every day.

    Thang-ga is a special kind of painting. It started from the Tang Dynasty. Thang-ga paintings have attracted the public's attention in recent years. At the same time, the Chinese government has also tried hard to protect the culture.

    Thang-ga paintings were developed in the 7th century in the Tibetan area. The paintings are colourful and the paints used in Thang-ga paintings are different from those in other paintings. Because of the special environment of the Tibetan Plateau (高原) and the excellent painting skills, the colours of Thang-ga paintings look special. The paints in Thang-ga paintings in the past were made from minerals, including gold, silver, as well as some plants. Since they were made by hand, the beautiful colours could last for hundreds of years.

    However, with the development of machines, people now use cheaper and more easily-made chemicals to make paints. The traditional paints in Thang-ga paintings needed too much work and there were many secret methods. Later people stopped making the paints and forgot about them. So the skills were almost lost.

    Beauty sleep is a real thing, researches have shown that people who have enough sleep look more attractive (有魅力的) to others.

    A few bad nights are enough to make a person look especially "more ugly", their sleep experiments show.

    The researchers asked 25 university students to join in their sleep experiment. They were asked to get a good night's sleep for two nights.

    A week later, they were asked to sleep for only four hour every night for two nights in a row. The researchers took make—up free (素颜) photos of the volunteers after both the good and the bad sleep.

    Next, they asked 122 strangers to have a look at the photos and judge (评价) them on attractiveness, health, and sleepiness, as well as asking them: "How much would you like to make friends with this person in the picture?"

    The strangers were good at judging whether the person they were looking at was tired, and if he was sleepy, his attractiveness score would be low.

    The strangers also said they wouldn't want to socialize with the tired students. The researchers say this is natural for people. An unhealthy-looking face makes people run away. In other words, people don't want to hang around with people who might be ill.

    Dr Brewer, an expert at the University of Liverpool said: "Judgment of attractiveness is often unconscious (无意识的), but we all do it, and we are able to judge on even something small like whether someone looks tired or unhealthy. This study is a good reminder of how important sleep is to us."

    Grandparents are respected in many human societies. But telling stories about old times and overfeeding grandchildren seem like human qualities. Are these classic grandparent behaviors really limited to humans?

Do any animals know their grandparents the way people do?

For most species on Earth, the answer is certainly " No" . " Usually, there aren't grandparents around anymore when an animal is born,"  said Mirkka Lahdenpera, a biologist at the University of Turku in Finland. " Even if an animal's life span does overlap (重叠) with its grandparents', most species spread out to avoid competing for resources, so the chance of running into a grandparent is slim." 

But there are a few clear exceptions, primarily among mammals (哺乳动物) that live in close social groups. In troops of langur monkeys in India, older females lived together with their daughters and grandchildren. The grandmother langurs defend the group's babies against attacks and even give their own grandchildren special treatment.

Many whale species, too, travel in family groups that include both grandmothers and grandchildren.

Elephant herds are also famously matriarchal. They are led by a grandmother, who can live to around 80 years old, and are generally made up of her daughters and their young. The females in a herd form close bonds and work together to raise their young.

Lahdenper found that the babies of young mothers were eight times more likely to survive if their grandmothers lived near them than if they didn't. When the young mothers were older and more experienced at raising babies, this beneficial grandmother effect disappeared even if the actual grandmothers were still around.

Indeed, most evidence for the benefits of grand parenting comes from mammals. But in 2010, researchers found that in troops of insects called gall-forming aphids, older females defend their relatives after they've stopped reproducing (繁殖).

And what about grandfathers? Studies of humans in recent decades have shown that a living grandfather can improve a person's mental health and other indicators of well-being. But there's no evidence of that in the animal kingdom. Male animals rarely socialize with their own children, let alone any grandchildren.

Many people take running as a way to keep fit. They like to run in hot weather and enjoy the feeling of being wet through with sweat (汗) while running. Cold weather during winter months, with low temperatures and freezing cold winds, may keep people from running in the open air.

However, a new study shows that the drop in temperature is a good reason to run. In fact, running in cold weather helps improve one's performance. Many runners might find it easier to run in winter than in hot weather. The body needs less water on a cold day than in warm weather. In addition, lower temperatures reduce stress on the body. When you run in cold weather, your heart rate is lower.

John Brewer is a professor of applied sports science at St. Mary's University in London. For this study, he and other researchers put a group of people into a room where summer and winter weather conditions are recreated. The test subjects were asked to run 10,000 meters under both conditions and their biological measurements were recorded and studied.From the study, every movement runners make produces heat. The heat can be really damaging unless the body can lose it. One way in which people lose heat is by sweating. The body loses heat through sweat. The body also loses it by transporting the blood to the surface of the skin and it puts more stress on the heart, especially in hot conditions because it's much harder to lose heat when the outside environment is warm. As the result shows, running in hot temperatures results in 6 percent higher heat rates.

When running in cold conditions, the body does not have to work hard to move blood to the skin surface. Therefore, it requires less energy. The most important thing for people who run in cold conditions is to wear the right clothing. Keep as dry as possible when exercising in low temperatures. Wear warm and light clothing to keep sweat away from your skin. So don't let winter weather keep you indoors. Simply get ready for the low temperatures and start running.

What did people do to communicate in ancient times? Here are some very interesting answers to this question.

Alphorns（阿尔卑斯长号角） were once used to communicate in the mountains in Switzerland. They are very long and they are very heavy, too. So, alphorns are hard work to blow. Then why use them? Well, they make a loud sound which travels much further than the human voice. Herdsmen（牧民） used them to call cows in the distance for milking. At sunset, alphorns were also used to send a message down to villagers that all was well. These days, they're mostly used as musical instruments.

The people of La Gomera, an island in Europe, have their own special way of sending messages from mountain to mountain. They use a whistled（口哨） language called el silbo, which comes from their language Spanish. Whistling can be heard within five kilorneters, which means it can be used across much greater distances than shouting. El silbo can be used for all kinds of messages, including greetings and announcements. El silbo is used a lot less than it used to be, but primary school students in La Gomera have to leave it.

Did you know it 's also possible to send messages without making a noise? This is called visual communication, and it includes the use of flags and even smoke. Long ago, soldiers along the Great Wall of China used smoke as a warning. If they noticed the enemy from their signal（信号） tower, they lit a smoky fire. When soldiers in other towers saw the smoke signal, they lit fires, too. In this way, messages about the enemy's arrival could travel as far as 800 km in just a few hours.