Sleep Struggle

     One in every five young people has a sleep problem, so you're not alone. Getting enough sleep has become as important as eating vegetables and exercising regularly. It's very important for your body.

     Most young people only get seven hours of sleep each night, when they actually need nine hours. And making up for lost sleep during the week by sleeping on weekends doesn't really work. In fact, sleeping late on weekends may actually do you more harm than good, if you have sleep problems.

     What happens if you don't get enough sleep? If your sleep problem continues for a few nights, you could suffer serious problems. Lack of sleep can affect learning and memory. Worse, if your sleep difficulties last a long time, that could lead to anxiety (焦虑). Therefore, you've got to have some healthy sleep habits. Below are some suggestions:

     •Go to bed at the same time—including weekends, if possible.

     •Wake up around the same time every morning. When you sleep late just one morning during the week, it may disturb your body clock. This will make it hard for you to sleep that night.

     •Do something relaxing before going to bed.

     •Exercise during the day. Don't exercise right before going to bed.

     •Avoid drinking. Alcohol (酒精) makes you excited. This prevents you from falling asleep or wakes you up during the night.

     •Don't smoke. Smoking is always bad for the body. Smoking before bedtime keeps you awake.

     If trying these tips over a couple of weeks does not help you, speak to your doctor. Do not take any medicine without first asking your doctor. Many of them have strong side effects.

    The clock struck eleven at night. The whole house was quiet. Everyone was in bed except me. Under the strong light, I looked sad before a huge pile of troublesome stuff that were called “books”. I was going to have my exam the next day. "When can I go to bed?" I asked myself. I didn't answer; as a matter of fact, I dared not.

    The clock struck twelve. "Oh, dear!" I cried, "five more books to read before I can go to bed!” We pupils are the poorest in the world. Dad does not agree with me on this. He did not have to work so hard when he was a boy.

    The clock struck one. I was quite hopeless now. I forgot all I had learnt. I was too tired to go on. I did the only thing I could. I prayed, “Oh, God! Please help me pass the exam tomorrow. I do promise to work hard afterwards, Amen.” My eyes were so heavy that I could hardly open them. A few minutes later, with my head on the desk, I fell asleep.

    Plastic is easy, convenient, cheap and long-lasting, but it does great harm to the environment.

    Since plastic entered mass production, 8 billion tons have been produced – and we aren't very good at recycling. By 2015, 6,945 tons of plastic waste had formed, with around 9 percent of it getting recycled. About 79 percent of it ends up in landfills or around the environment, including the ocean. We may end up drowning in plastic before long.

    Chemists at Colorado State University have found a polymer（聚酯）that has many of the qualities of plastics – it's light, strong, durable and heat-resistant – but that can be changed back to its original small-molecule（分子）state for complete recycling. Even after being recycled, the polymer can be turned back into its plastic-like state, and this can be done quickly and cheaply.

    This new polymer has all the good qualities of plastics, yet it is relatively easy to make and to recycle. Making it requires room temperature conditions, a short reaction time to bond the monomer（单体）into polymers and only a small amount of the catalyst（催化剂）remains in the end product. It has a high molecular weight, stands up to heat and generally behaves like plastic. Recycling it requires similarly little effort. Mild lab conditions are required and so is a catalyst. Once applied, the polymers are once again monomers in a matter of minutes and can be used to create another product.

    But don't get too excited about this just yet. Scientists stressed that the polymer isn't ready for mass products just yet. There's still plenty of development to do, including making it more economical to produce and recycle.

    If a diver surfaces too quickly, he may suffer the bends. Nitrogen(氮) dissolved(溶解) in his blood is suddenly liberated by the reduction of pressure. The consequence, if the bubbles (气泡)accumulate in a joint, is sharp pain and a bent body—thus the name. If the bubbles form in his lungs or his brain, the consequence can be death.

    Other air-breathing animals also suffer this decompression(减压) sickness if they surface too fast: whales, for example. And so, long ago, did ichthyosaurs. That these ancient sea animals got the bends can be seen from their bones. If bubbles of nitrogen form inside the bone they can cut off its blood supply. This kills the cells in the bone, and consequently weakens it, sometimes to the point of collapse. Fossil (化石)bones that have caved in on themselves are thus a sign that the animal once had the bends.

    Bruce Rothschild of the University of Kansas knew all this when he began a study of ichthyosaur bones to find out how widespread the problem was in the past. What he particularly wanted to investigate was how ichthyosaurs adapted to the problem of decompression over the 150 million years. To this end, he and his colleagues traveled the world's natural-history museums, looking at hundreds of ichthyosaurs from the Triassic period and from the later Jurassic and Cretaceous periods.

    When he started, he assumed that signs of the bends would be rarer in younger fossils, reflecting their gradual evolution of measures to deal with decompression. Instead, he was astonished to discover the opposite. More than 15% of Jurassic and Cretaceous ichthyosaurs had suffered the bends before they died, but not a single Triassic specimen(标本) showed evidence of that sort of injury.

    If ichthyosaurs did evolve an anti-decompression means, they clearly did so quickly—and, most strangely, they lost it afterwards. But that is not what Dr Rothschild thinks happened. He suspects it was evolution in other animals that caused the change.

    Whales that suffer the bends often do so because they have surfaced to escape a predator (捕食动物) such as a large shark. One of the features of Jurassic oceans was an abundance of large sharks and crocodiles, both of which were fond of ichthyosaur lunches. Triassic oceans, by contrast, were mercifully shark- and crocodile-free. In the Triassic, then, ichthyosaurs were top of the food chain. In the Jurassic and Cretaceous, they were prey(猎物) as well as predator—and often had to make a speedy exit as a result.

    Dr. Michael Prager, a leading Botox expert, said that a growing number of women are developing something called "computer face". He also mentioned that professionals who worked long hours in front of a screen were ending up with saggy jowls(颚骨下垂),"turkey neck" and deep-set wrinkles(皱纹)on their forehead and around their eyes.

    The Botox expert said that, of all his clients, office workers were most likely to show premature (过早的)signs of aging. " If you are one of the unfortunate people who frown(皱眉)while you are concentrating on the screen then, over time, you will inevitably(不可避免地)end up with frown lines.'' Dr. Prager said. "What is perhaps more surprising is the number of women with saggy jowls because they are sitting in one position for so long. If you spend most of the time looking down then the neck muscles shorten and go saggy, eventually giving you a second neck."

    Dr. Prager, who has a practice near Harley Street in London, said he encourages his clients to put a mirror next to their computer so they can see if they are frowning at the screen. "When people are stressed or thinking hard about something, then they will often put on a grumpy(脾气暴躁的)face' without even knowing what they are doing. When my clients put a mirror next to their desk, they are often shocked by the angry, frowning face which stares back at them."

    He said, "The women I am seeing at the moment have only been using computers at work for the last decade or so. But women in their 20s have grown up with them and use them for every single task. I think the problem is going to become much, much worse. In another ten years, they could be looking quite awful."

    Dr. Prager said there were several simple steps which could avoid "computer face" such as regular screen breaks and stretching the neck muscles. And, of course, there was always Botox(肉毒杆菌). He said that, after a couple of sessions of Botox, the habit of "grumpy face" could be broken.

    The English language has a lot of words which can be used in many different ways and in many different expressions.

    One such example is the word matter. In fact, matter can mean just about anything. It could be one of the most useful words in the English language.

    Let's get to the heart of the matter—a matter of principle (原则).

    If someone says that you owe (欠) him $50, but you don't, a friend might say, "Well, you could pay him the $50. It's not that much money. Then you won't have to hear him say it anymore." But if you do not owe him the money, do not pay him the money. It's a matter of principle.

    There is another way to use the word matter. But be careful with your choice of words.

    If you ask someone, "What's the matter?" it shows you are worried about the other person. But saying, "What's the matter with you?" has a completely different meaning. And it usually sounds rude (粗鲁的). In fact, when you say, "What's the matter with you?" you are suggesting that the person did something wrong or stupid.

    Another expression that could sound rude is to say, "It doesn't matter to me." Here, it depends on the context, and how you say it.

    Let's say you tell someone that a friend just got a big raise at work. That person answers with, "It doesn't matter to me." Here, it means he or she does not care. And it sounds rude.

    But saying, "Oh, you pick where we eat dinner. It doesn't matter to me." does not sound rude. In this situation, "it doesn't matter" shows you are easy-going (随和的).

    No matter how you look at it and what you say, matter is a very useful word. And it's only a matter of time before you will become an expert on the use of matter.