Are you carrying too much on your back at school? You're not alone. Back experts (专家) in the USA are worried about that young students are having back and neck problems because they are carrying too much in their backpacks .

    “It hurts my back when I run,” said Ebelin Reyes, a student in Virginia. “It's hard to get up the stairs with my backpack because it's too heavy.” Students have to carry heavy backpacks on their backs for a whole week's study. Ebelin is one of them. They have regular (固定的) backpacks with two straps (带子) to carry them, but a number of students with heavy loads (负担) have switched to rolling backpacks. The backpacks have wheels and can roll on the ground. Shirley Park's backpack weighs 10 kilos, and she said, “I'll change to a rolling backpack because I am starting to have back pain.”

    How much is too much? Experts say that students should carry no more than 10% to 15% of their own body weight. A few students have had a good idea to lighten (减轻) the load: less homework.

Doctor's suggestions:

⑴Lighten the load. Take home only the books the students need that day.

⑵Wide straps are better. They can send out weight over your shoulders (肩) and be sure to wear backpacks with two straps.

⑶The heaviest things should be packed closest to the back.

⑷Bend (弯曲) both knees when you pick up the pack, don't just bend over the waist (腰).

    If you want to become a fluent English speaker you should take some advice. There are four skills in learning English. They are reading, listening, speaking, and writing. The most important thing you must remember is that if you want to improve your speaking and writing skills, you should first master the skills of reading and listening.

    Read as much as you can. But your reading must be active. It means that you must think about the meaning of the sentence, the meaning of the unfamiliar words, etc. There is no need for you to pay much attention to grammars or try to understand all the unfamiliar words you come across, but the fact that you see them for the first time and recognize them whenever you see them, for example, in other passages or books, is enough. It would be better to prepare yourself a notebook so you can write down the important words or sentences in it.

    As for listening, there are two choices: besides reading, you can listen every day for about 30 minutes. You can only pay attention to your reading and become skillful at your reading, then you can catch up on your listening. Since you have lots of inputs in your mind, you can easily guess what the speaker is going to say. This never means that you should not practice listening. For listening you can listen to cartoons or some movies that are specially made for children. Their languages are easy. Or if you are good at listening you can listen to VOA or BBC programs every day. Again the thing to remember is being active in listening and preferably taking some notes.

    If you follow these pieces of advice, your speaking and writing will improve quickly, and you can be a fluent English speaker one day.

    As a gesture of friendship，Mayor Yukio Ozaki of Tokyo，Japan gave Washington, D.C a gift of more than 3,000 Japanese cherry trees on March 17,1912.Every spring, the cherry trees in Washington，D.C. take bloom(开花)，beginning one of the country's loveliest celebrations, the National Cherry Blossom Festival (March 17-April 15). Book your trip now to see this vibrant display of pink and white in this city full of history!

    Washington, D.C. Cherry Blossom In-Depth Tour

    Priee: $45/person

    Available: Mar.25-Apr.15

    Duration: 1 Day

    Highlights: Visit Washington， D.C.; experience the peak period of cherry blossom(April 8-12)

    Itinerary: Guests will start to celebrate the National Cherry Blossom Festival and discover the beauty of cherry blossoms. Next,we will begin our sightseeing city tour including Lincoln Memorial, White House, US Capitol, Madame Tussauds Wax Museum, Washington Monument and International Spy Museum. Then visit the next tourist spot, the Jefferson Memorial. It's the best location to view the cherry blossoms. Finally, guests may board a Potomac River cruise to see the city from the water. Then tour ends.

    Price Includes: Ground Transportation

    Admission Fees:

    Note: If you would like to join in the optional activities, please pay the fee in cash to the tour guide. You cannot buy the tickets on your own or use City Pass. The tour guide will arrange the tickets for the group.

    A nine-year-old kid was sitting at his desk when suddenly there was a puddle（水潭、泥坑） between his feet and the front of his trousers was wet. He thought his heart was going to stop because he couldn't possibly imagine how this had happened. It had never happened before, and he knew that when the boys found out he would never hear the end of it. When the girls found out, they would never speak to him again as long as he lived.

    He prayed this prayer, "Dear God, I need help now! Five minutes from now I'm dead meat!" He looked up from his prayer and here came the teacher with a look in her eyes that said he had been discovered. As the teacher was walking toward him, a classmate named Susie was carrying a goldfish bowl full of water. Susie tripped （绊倒） in front of the teacher and dumped （倒） the bowl of water in the boy's lap. The boy pretended to be angry, but all the while was saying to himself, "Thank you. Lord!"

    Now all of a sudden, instead of being the object of ridicule, the boy was the object of sympathy. The teacher rushed him downstairs and gave him gym shorts to put on while his trousers dried out. All the other children were on their hands and knees cleaning up around his desk. The sympathy was wonderful. But as life would have it, the ridicule that should have been his had been transferred （转移） to someone else+—Susie. She tried to help, but they told her to get out.

    When school was over, the boy walked over to Susie and whispered, "You did that on purpose, didn't you?" Susie whispered back, "I wet my trousers once, too!"

    Think plants are just boring green things that you use for food and decoration? Think again! Plants are able to do some pretty awesome things that you're probably totally unaware of.

    Researchers have discovered that plants have the ability to communicate with an underground network made up of fungus (真菌) , which serves the plants in many ways. Tomato plants use the fungus web to warn each other of their own unhealthy conditions. Trees connected through the fungus network could move nutrients (养分) to and from each other. It is believed that larger trees move nutrients to smaller ones to help them to survive.

    Not only that, but they can also damage unwelcome plants by spreading poisonous chemicals through the fungus. It sounds like the plant world had the Internet before we did.

    Some plants have a rather impressive line of defense against being eaten. When sensing they are being swallowed, they give off a chemical into the air that attracts the insect's natural enemy. The enemy attacks the bug, thus saving the plants. This is basically the plant kingdom version of getting your older brother to beat up that kid who steals your lunch money.

    You might be aware that humans and animals have an internal clock. But did you know that plants also have this clock? This means they can prepare for certain times of day just like we do. Is it because they can react to light at sunrise? In a study, scientists found that plants use the sugars they produce to keep time, which help to regulate the genes responsible for the plant's own internal clock. So, in a sense, wake up with petunias (矮牵牛) is just as valid as ―wake up with the chickens.

    Nature is full of surprises. So for those of you who didn't know the wonders of plants, now you do.

Perhaps you have seen them, those who fall asleep on the subway and then, somehow, wake up exactly at their stop. Perhaps you are one of them. How is this possible? We spoke to two doctors, who offered their insights about it.

It is possible that your body gets used to waking up at a certain point each time during your commute, said Dr. Marc I. Leavey, a primary-care specialist in Maryland. That holds especially true if you commute at the same time every day. This suggests that if you were to get on at a different time, or if the journey were delayed, your internal clock might not wake you up at your stop. It is an interesting theory, but Dr. Ronald Chervin, director of Michigan Medicine's Sleep Disorders Centers, does not fully buy it. He is skeptical that circadian rhythms can also explain why you wake up after a brief nap.

You are also likely to wake up for your particular stop because of an oral cue, such as the conductor stating the name of the subway stop over the public-address system. Such cues alert your brain that you have arrived, explained Dr Leavey. According to a study published in the Public Library of Science, during sleep, our brain reacts differently when we hear our own name and other people's names, noted Dr Chervin. This suggests that your brain does not turn off during sleep, which makes it possible to pick up on the announcement of your stop.

Another reasonable possibility: You may wake up at each stop, check if it is yours, and go back to sleep, all without having remembered it, added Dr. Chervin. He sees this in cases where patients are suffering from sleep apnea. They may wake up as many as 200 times during a single night, without having remembered a single instance. That's because they fall right back asleep before their brain has time to process their experience into long-term memory. Similarly, you could be waking up every time you hear a new stop called. But you just don't remember such instances even after you fully come awake for your stop—leading you to believe that you have slept the whole way through and miraculously woken up at the right time.