Deserts are found where there is little rainfall or where rain for a whole year falls in only a few weeks' time. Ten inches of rain may be enough for many plants to survive if the rain is spread throughout the year. If it falls within one or two months and the rest of the year is dry, those plants may die and a desert may form.

    Sand begins as tiny pieces of rock that get smaller and smaller as wind and weather wear them down. Sand dunes (沙丘) are formed as winds move the sand across the desert. Bit by bit, the dunes grow over the years, always moving with the winds and changing the shape. Most of them are only a few feet tall, but they can grow to be several hundred feet high.

There is, however, much more to a desert than sand. In the deserts of the southwestern United States, cliffs (悬崖) and deep valleys were formed from thick mud that once lay under a sea more than millions of years ago. Over the centuries, the water dried up. Wind, sand, rain, heat and cold all wore away at the remaining rocks. The faces of the desert mountains are always changing –-very, very slowly —as these forces of nature continue to work on the rock.

    Most deserts have a surprising variety of life. There are plants, animals and insects that have adapted to life in the desert. During the heat of the day a visitor may see very few signs of living things, but as the air begins to cool in the evening, the desert comes to life. As the sun begins to rise again in the sky, the desert once again becomes quiet and lonely.

    It's summer movie time again. And heroes are ready to try their strength and magic on the silver screen. Check out our list of four films that look most promising to young audience.

    Harry potter and the Prisoner of Azkaban

    Release Date:  June 4

    Story: It's the summer before Harry Potter's third year at Hogwarts School of Witchcraft and Wizardry. A shadow is hanging over Hogwarts. A dangerous murderer, Sirius Black, has escaped the Wizards' Prison. And he broke out to fulfill one task to kill Harry Potter.

    Around the World in 80 Days

    Release Date:  June 16

    Story: This version of the classic novel set in 1872 focuses on Passepartout (Hong Kong actor Jackie Chan), a Chinese thief who seeks refuge with a strange London adventurer, Phileas Fogg. Passepartout uses his martial arts skills to defend Fogg from danger as he travels around the world in 80 days to win a bet.

    Spider- Man 2

    Release Date: June 30

    Story :Peter Parker is still coming to terms with his dual  identity (双重身份)as the crime superhero Spider-Man. He wants to reveal his secret identity to Mary Jane: meanwhile, his aunt May has fallen on hard times. A new bad man, Dr Otto Octavius, has appeared to cause more troubles.

    King Arther

    Release Date: July 7

    Story: King Arthur is presented as a clever ruler who manages to unite all the knights(骑士) in Britain after the fall of the Roman Empire(帝国). Under the guidance of Merlin and the beautiful, brave Guinevere, Arthur will struggle to realize his dreams

    There was a doctor in our city who was famous for his skills. Once he received a little child who was badly ill. Thanks to his skill and care, his young patient got well and was soon able to get up and run about again.

    The child's mother was very much thankful to the doctor, and she visited him to thank him for what he had done for her child. “Doctor,” she said, “you have saved my little son. I don't know how to thank you enough. I feel that money alone cannot repay you, so I have made this little purse with my own hands, as a sign of my gratitude. I hope you will accept it.” The doctor stood up and said coldly, “Madam, a little present like that is very nice between friends, but a doctor needs to be paid properly for what he has done.” The lady was so surprised and hurt so much that she could not reply for a moment. Then she said quietly, “Perhaps you will tell me how much your fee is?”

    “Fifty pounds”, he answered.

    The lady opened the little purse and took out four fifty-pound bank notes. She handed one of them to the doctor, and put the other three back into the purse. She put the purse into her handbag and, saying good bye to the doctor, went out of the room.

    We've all heard the saying: practice makes prefect! In other words, acquiring skills takes time and effort. But how exactly does one go about learning a complex subject such as tennis, calculus, or even how to play the violin? An age-old answer is: practice one skill at a time. A beginning pianist might rehearse scales(音阶) before chords(和弦). A young tennis player practices the forehand before the backhand. Learning researchers call this “blocking”， and because it is common and easy to schedule, blocking is dominant in schools, training programs, and other settings.

    However another strategy promises improved results. Enter “interleaving”， a largely unheard-of technique that is catching the attention of  cognitive(认知) psychologists and neuroscientists. Blocking involves practicing one skill at a time before the next (for example, “skill A” before “skill B” and so on, forming the pattern “AAABBBCCC”), while in interleaving one mixes practice on several related skills together (forming for example the pattern “ABCABCABC”).

    Over the past four decades, a small but growing body of research has found that interleaving often outperforms blocking for a variety of subjects, including sports and category learning. Yet there have been almost no studies of the technique in unplanned, real world settings-until recently. New research in schools finds that interleaving produces dramatic and long-lasting benefits for an essential skill: math. Not only does this finding have the potential to transform how math is taught, it may also change how people learn more generally.

    Researches are now working to understand why interleaving produces such impressive results. One important explanation is that it improves the brain's ability to tell apart between concepts. With blocking, once you know what solution to use, or movement to do, the hard part is over. With interleaving, each practice attempt is different from the last, so rote(死记硬背) responses don't work. Instead, your brain must continuously focus on searching for different solutions. That process can improve your ability to learn critical features of skills and concepts, which then better enables you to select and produce the correct response.

    A second explanation is that interleaving strengthens memory associations. With blocking, a single strategy，temporarily held in short-term memory, is sufficient. That's not the case with interleaving-the correct solution changes from one practice attempt to the next. As a result, your brain is continually engaged at regaining different responses and bringing them into short-term memory. Repeating that process can strengthen neural connections between different tasks and correct responses, which improves learning.

    Both of these accounts imply that increased effort during training, either to discriminate correct responses or to strengthen them, is needed when interleaving is used. This corresponds to a potential drawback of the technique, namely that the learning process often feels more gradual and difficult in the beginning. However, that added effort can have better, longer-lasting results.

    I can't remember the first time one of my children told me, "I hate you." I can, however, tell you that it still happens occasionally, but it doesn't bother me. As their father, I often say things that are unpopular. If they hate me once in a while, I know I'm doing a good job.

    There are three other words that I won't allow in my house, however. Last week, I was watching my older son play with a paper airplane. After he accidentally threw it into a wall and it came apart, his eyes welled up with tears.

    "I hate myself," he said. It wasn't the first time he'd said it, and I was concerned that he'd started to actually believe it.

    I knelt down next to him and made him look into my eyes. I told him that I never wanted to hear those words again, and that he needed to respect himself.

    The difference between your kid telling you they hate you and them saying they hate themselves is that, five minutes later, they've already forgotten they "hate you". Self-hate is much more potentially poisonous and for young people, it can linger into the rest of their life.

    Kids who start to believe they hate themselves sometimes struggle to form new friendships. As teenagers, they avoid the chance to connect with a potential love interest, because they assume they'll be rejected. And as adults, they might choose not to apply for the dream job because they assume it won't work out.

    I know this is true, because I didn't have a high opinion of myself as a child. I found myself struggling in many areas, and I'd hate to see my children suffer the same fate.

    Sometimes, words are just words. But some words can make the kind of impact I'd very much like to avoid for my children. I don't fear strong language; I fear language that makes us weak.

    It is rightly said one can share any secret with a true friend. He may know your deepest fears and weaknesses and yet will never take advantage of you. However, keeping a friend's secrets to yourself and not telling the world is what makes the bond grow strong and last forever. You need to develop trust and mutual (互相的) understanding before you start sharing secrets with each other. With friends, secret talks never seem to end and it can get really amusing to know what has been going on in your friend's mind.

    There is a certain time in life especially from the teenage years when one starts having a personal periphery (界限) in life and parents are excluded (排斥) from it. It is because there are certain things that they can't understand and we can't discuss with them. That is when friends become the best secret sharers. They are the ones to whom one reveals one's feelings and best kept secrets.

    It is a general belief that only girls share secrets. But boys have their own secrets that they discuss with only closest friends. The secret talks can range (变化) from relationships, talks about fights with parents, secret activities and anything that is not supposed to be known to others! If you think secrets are limited to only teenagers, get your facts right! Secrets can be shared at any age and there is no hard and fast rule that secrets are shared only among youngsters.

    Sharing secrets with a friend is not just fun, but it also helps to develop a lasting trust in one another. Sometimes, sharing secrets will tell you more about the person. You will come to know whether your friend is reliable and trustworthy and whether it is worth sharing your secrets with them. You can call it a test of friendship.