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    Body language is one of the most powerful means of communication, often even more powerful than spoken language. People around the world show all kinds of feelings, wishes and attitudes that they might never speak aloud. It is possible to ―read‖ others around us, even if they do not want us to catch their unspoken communication. Of course, body language can be misread, but many gestures and actions are common.

    The most common facial expression is, of course, the smile – its function is to show happiness and put people at ease. It does not always mean that we are truly happy, however. Smiles around the world can be false, hiding other feelings like anger, fear or worry. There are unhappy smiles, such as when someone ―loses face‖ and smiles to hide it. However, the general purpose of smiling is to show good feelings.

From the time we are babies, we show unhappiness or anger by frowning (皱眉头). In most places around the world, frowning and turning one's back to someone shows anger. Making a fist (拳头) and shaking it almost always means that someone is angry.

How about showing that I am bored? Looking away from people or yawning will, in most cases, make me appear to be uninterested. However, if I turn toward and look at someone or something, people from almost every culture will think that I am interested.

    Being respectful to people is subjective, based on each culture, but in general it is probably not a good idea to give a hug to boss or teacher. In almost every culture, it is not usually good to stand too close to someone of a higher rank (等级). Standing at a little distance with open hands will show that I am willing to listen.

    With so many cultural differences between people, it is great to have some similarities in body language. We can often be wrong about each other, so it is an amazing thing that we understand each other as well as we do!

    Stop reading for a minute and think about what you see when you look up at the sky on a clear night. You probably see many stars (星星). Long long ago, farmers watch some stars to know when to plant their crops. Travelers did so to find their way in the dark. Today stars are still important to some people.

    Scientists find that most stars are very big. In fact some stars are so far away that it would take millions of years to get to them even by spaceship.

    Another thing we know today about stars is that some are made up of(由…组成) hot gases. The gases are so hot that they send out light. If you watch a star carefully, you may notice that it twinkles(闪烁)sometimes. As you may understand, light from a star must shine through the air before you can see the star. Air is always moving, it makes light from the star move back and forth. When the light moves, it makes the star twinkle. Stars also have different colors. The colors of a star depend on how hot it is. To our surprise, the cool stars are red and the hottest stars are white.

    Some primary schoolchildren have been raised in homes with more green space around. They are likely to come with larger volumes of white and grey matter in certain areas of the brain. These differences are associated(关联) with beneficial effects on cognitive function (认知功能). This is the main conclusion of a study led by the Barcelona Institute for Global Health.

    The study was performed among 253 schoolchildren in Spain .Lifelong exposure(接触) to green space in the living places was recorded—using the information on the children's addresses from birth up through to the time of the study. Brain structure was studied using 3D magnetic resonance imaging (MRI). Working memory and inattentiveness(注意力不集中)were graded with computers.

    “This is the first study that shows the association between long-term exposure to green space and brain structure.” Says Dr. Payam Dadvand, the leading researcher of the study, “Our findings suggest that exposure to green space early in life could result in beneficial structural changes in the brain.”

    The findings show that long-term exposure to greenness is positively associated with white and grey matter volumes in several parts of the brain. Some of them are related to higher scores on cognitive tests. Moreover, larger volumes of white and grey matter in those parts might lead to better working memory and less inattentiveness.

    Exposure to nature has been thought to be necessary for brain development in children. Another study of 2,593 children shows that children in school with more green space have a greater increase in working memory and a greater decrease in inattentiveness.

    Humans are believed to be tied to nature.  Playing in greener areas offers children opportunities to search and learn. Accordingly, green space is thought to prompt important exercises in discovery, creativity and risk taking. These exercises in turn positively influence brain development.

    Dr. Dadvand's study suggests how such structural changes could bring about the beneficial effects of green spaces on cognitive development, it also adds to the proof that suggests the lasting effects of early life exposure to greenness on our health and the benefits of increasing greenness in cities.

    Further studies are needed to prove the findings in other populations, settings and climates. And researchers need to examine differences according to the nature and quality of green space.

    Birdwatching is a fun hobby. Many people enjoy it every day. You can also enjoy it. Birdwatching does not have to take a lot of time or money. With materials(材料) around your house, you can build a good birdhouse. You can start birdwatching in 30 minutes in your very own yard. It's very easy!

    Materials you will need:

    Milk box        ●Glue        ●Scissors      ●Brown paint        ●Tools for painting

    To build a better birdhouse

    ⒈Clean and dry the milk box.

    ⒉Glue the top of the milk box shut.

    ⒊Cut holes into the milk box for the birds to get into the birdhouse. The size you use will determine which birds use the house. You can cut one hole per side, or two. A good place to cut is about four inches(英寸) from the bottom(底部).

    ⒋Paint your milk box brown. The color helps the birdhouse mix with the tree.

    ⒌Cut holes into the milk box in the bottom of the box to let out any dirty things. Add at least two small holes on the top of the box. The top holes are to let in clean air. Do this after painting, or the paint could fill in your holes!

    ⒍Put the box in a tree. You can see the birdhouse from a window of your house. Now you can watch your birds in any weather!

    Like humans, dogs donate blood too, and not every dog can donate blood. The dogs are screened(检查) for health first. Dogs must have the correct blood type, weigh at least 55 pounds and be younger than 8 years old. They may donate three or four pints(品脱) a year, which can help animals that are suffering from illnesses like cancer or an accident like being hit by a car. One pint can save up to three dogs.

    Owners volunteer their pets for the short procedure (程序), which requires no sedative, a kind of medicine given to calm him or her down. It's the dog that finally chooses to lie still and give. If the dogs want to get up and leave, they can.

    Sandy Lucas brought her 7-year-old black German shepherd, Rains, to the bloodmobile(流动血站) when it was parked at her small village. Sandy said she wouldn't have troubled herself with highway traffic and city parking problems to take the dog to Penn Vet's animal hospital in downtown Philadelphia, which is twice as far as her home. But the bloodmobile made it easy to find out if Rains could donate. "I was very, very excited that she had the right blood that was needed to help another dog out," said Sandy. "We'll surely do it again."

    When the Audet family turns on the lights at Blue Farm, they are using electricity that comes from cows- cow manure(粪肥).

    Cows produce a lot of waste. One cow can create 30 gallons of waste each day. Now imagine the output of over 1,000 cows at Blue Farm. That's really a big amount.

    When farmers clean their barns, they put the waste together，and spread some of it on their fields for fertilizer(肥料). But now places like Blue Farm have a new way of using cow waste. They use it to produce electricity.

    Here's how it works: A big machine moves back and forth cleaning the barn floor. "The cows are animals of habit; they get used to it,and just lift one foot and then another to let it go by. "says Marie Audet.

    The machine pushes the manure into a big 600-gallon tank like a small swimming pool. The tank is called a digester(化粪池) because what happens there is just like what happens inside a cow: Bacteria(细菌) get to work and continue to digest the manure.

    Methane gas(甲烷;沼气) in the atmosphere is known as a "greenhouse" gas because it keeps heat just like a greenhouse does, causing our planet to warm up. That's an environmental concern. But the digester has a good result. Its gas is kept and used to power electric generators(发电机).

    At Blue Farm, the generators make enough electricity to power 400 homes. The Audet family sells the extra electricity they can't use themselves.