As the population of the planet increases, so does the number of homes, business, parking lots, schools, airports and roadways. All these structures use electricity and need to be lighted. Humans demand light. They want their homes more comfortable and they want their streets safe. The problem is that researchers are finding that all the light is having a negative effect on humans and wildlife as well.

    Less than 10 years ago I drove to a thinly populated section of my own, lay down in the middle of the road and watched an attractive meteor shower(流星雨). If I did that today, I wouldn't be able to see the meteor shower.

    Nowadays scientists are finding light pollution can be almost as bad as carbon dioxide （二氧化碳）pollution. One of the saddest parts of light pollution is that most of it is unnecessary and most of the outdoor light that we use is wasted. One only needs to look at a row of street lights to see how much of the lights shines upwards and lights the sky: a total waste of electricity.

    Additionally, the production of electricity creates pollution by releasing greenhouse gases. This affects the air we breathe and our quality of life.

    Scientists are also studying the effects of light pollution on wildlife. Thousands of birds die each year when they crash into highly lighted buildings, as they become puzzled by the light. It has been long known that tiny baby sea turtles become lost and follow the light on the shore instead of heading towards the sea.

    Fortunately, light pollution is one of the easiest sources of pollution that can be corrected without a negative effect. Following some guidelines and a little searching on Google can give you many ideas on how to reduce your contribution to light pollution.

    As a teenager, you may listen to stories often. But have you ever been a storyteller?{#blank#}1{#/blank#}The following are some tips:

    Who will listen?

    Will you tell your story to children of your own age? Will they are friends or young people you haven't met before? Perhaps you will tell it to younger children. Or, well it be an audience of adults?{#blank#}2{#/blank#}

    Why are you telling it?

    {#blank#}3{#/blank#}Knowing why you are telling it may be the most helpful reason for choosing a story for a particular audience. Many storytellers choose tales just to entertain(娱乐). They tell jokes or silly stories. Others want to teach something, such as how to be kinder to animals, the environment, or other people.{#blank#}4{#/blank#}Some babysitters tell stories to help children feel not afraid of thunder, lightning or scary shadows in their rooms. Others want to make people think or to help people remember. Some like to tighten other audiences with ghost stories.

    {#blank#}5{#/blank#}

    How you tell your story and what story helpers you use depend on where you will be speaking. Will you be taking at an evening party, in your classroom, in a library storytelling program, at a family dinner, at a museum, at a storytelling festival, or during a religious program?

A. One storyteller likes to encourage his listeners to try new things.

B. Will it be just a few people, a small group, or a large audience?

C. Generally, a story should be interesting.

D. Where will you speak?

E. When will you speak?

F. There are many reasons for telling a story

G. And do you know how to tell a story?

How teens can stay fit

    Any type of regular physical activity can improve your fitness and your health. {#blank#}1{#/blank#}

    Exercise should be a regular part of your day, like brushing your teeth, eating and sleeping. It can be in gym class, joining a sports team, or working out on your own. Keep the following tips in mind:

    {#blank#}2{#/blank#} A good attitude is important. Find an activity that you think is fun. You are more likely to stick with it if you choose something you like. A lot of people find it's more fun to exercise with someone else, so see if you can find a friend or family member to be active with you.

    Take a small step at a time. {#blank#}3{#/blank#} For example, walk or ride your bike to school. Get on or off the bus several blocks away and walk the rest of the way. Use the stairs instead of taking the elevator.

    Get your heart pumping (跳动). Whatever you choose, make sure it includes aerobic (有氧的) activity that makes you breathe harder and increases your heart rate. This is the best type of exercise because it improve your fitness and makes your heart work better. {#blank#}4{#/blank#} Examples of aerobic activities are basketball, running, or swimming.

    Don't forget to warm up. with some easy exercises or stretching (拉伸) before you do any physical activity. {#blank#}5{#/blank#} It is also important to stretch out after you exercise to cool down your muscles.

A. It also helps you to lose weight.   

B. Stay positive and have fun.

C. Make physical activity a habit.    

D. Small changes can add up to better fitness.

E. The most important thing is that you keep on it!

F. This warms your muscles up and may help protect against injury.

G. Do the activity as often as possible, but don't exercise to the point of pain.

Drinks Have No Wings

    You may have heard that "Red Bull gives you wings". But while most people take the advertising slogan as a metaphor(隐喻), some Americans seem to have taken it very seriously.

    Benjamin Careathers had been drinking the drink for 10 years, expecting to at least feel more energetic, but nothing happened. Feeling fooled by the ad, he took the issue to court.

    In October, the Austria-based company agreed to pay $ 6.5 million (39.7 million yuan) to customers who have bought the drink since 2002. People in the US can apply for a share through energydrinksettlement.com before March 2015.

    But is the case really that ridiculous?

    Red Bull said they had done nothing wrong and they only paid the money to save the cost and trouble of legal action.

    However, the suit(诉讼) told a different story. Even though there is no evidence that Red Bull energy drinks provide more benefit for consumers than a cup of coffee, the company markets their products as a superior source of energy that costs little.

    "Such conduct means that Red Bull's advertising and marketing is not just 'puffery' (吹捧) but is misleading and therefore actionable (可诉讼的) ," the suit said.

    The company said that the drink could promote healthy joints and reduce the risk of eye diseases. However, according to the organization, the product contains a lot of sugar, which could actually lead to many health problems.

    Coca-Cola agreed to pay $ 1.2 million in compensation in July. But to fully stop the company from linking the drink to health benefit, Truth in Advertising, another non-profit organization, took the issue to court again in late October.

    False advertisements have become a common problem around the world. China changed its consumer rights last year to ban advertising companies and media from making or publishing false advertisements. Celebrities are also made responsible if they endorse (代言) false or substandard products.

    My mother is a diligent and kind woman. She is very busy from morning till night. As a teacher, she works hard. {#blank#}1{#/blank#} Both my brother and I love her dearly as she loves us.

    My mother has been teaching math at a middle school in my hometown. She goes to work early in the morning and does not return home until late in the afternoon. {#blank#}2{#/blank#}  She treats them with patience and teaches them well. For her excellent quality and very good teaching results, she has been elected as a model teacher several times.

    {#blank#}3{#/blank#} Every day, when she comes back home from work, she sets about doing housework, sweeping the living room and bedrooms or cleaning the furniture, and putting everything in good order. She seems to be busy all the time. As she has been very busy working every day, she looks older than her age. But she looks as cheerful and happy as ever. Mother never buys expensive dresses for herself, but she often buys some inexpensive but high quality clothes for us. {#blank#}4{#/blank#} . She just eats a plain meal outside when she is too busy to cook herself. She lives a busy yet simple life, without any complaints.

    Often she says to us, “work while you work, and play while you play. That is the way to be happy and gay. If you do not work, you will become lazy and be of no use to society”. What a piece of good advice this is! {#blank#}5{#/blank#}. This advice of hers will always serve as a guide to my behavior. My mother is great indeed, and I always feel proud of her.

A. She enjoys listening to classic music.

B. As a mother, she takes good care of us and gives us every comfort.

C. She loves her students and cares for them.

D. She never goes to expensive restaurants to enjoy meals.

E. My mother is hard-working and never wastes money.

F. Can you tell us something about your mother?

G. I never forget it and always bear it in my mind

Life in the Clear

    Transparent animals let light pass through their bodies the same way light passes through a window. These animals typically live between the surface of the ocean and a depth of about 3,300 feet — as far as most light can reach. Most of them are extremely delicate and can be damaged by a simple touch. Sonke Johnsen, a scientist in biology, says, "These animals live through their life alone. They never touch anything unless they're eating it, or unless something is eating them."

    And they are as clear as glass. How does an animal become see­through? It's trickier than you might think.

    The objects around you are visible because they interact with light.  Light typically travels in a straight line. But some materials slow and scatter (散射) light, bouncing it away from its original path. Others absorb light, stopping it dead in its tracks.  Both scattering and absorption make an object look different from other objects around it, so you can see it easily.

    But a transparent object doesn't absorb or scatter light, at least not very much. Light can pass through it without bending or stopping. That means a transparent object doesn't look very different from the surrounding air or water. You don't see it — you see the things behind it.

    To become transparent, an animal needs to keep its body from absorbing or scattering light. Living materials can stop light because they contain pigments (色素) that absorb specific colors of light. But a transparent animal doesn't have pigments, so its tissues won't absorb light. According to Johnsen, avoiding absorption is actually easy. The real challenge is preventing light from scattering.

    Animals are built of many different materials — skin, fat, and more — and light moves through each at a different speed. Every time light moves into a material with a new speed, it bends and scatters. Transparent animals use different tricks to fight scattering. Some animals are simply very small or extremely flat.  Without much tissue to scatter light, it is easier to be see­through. Others build a large, clear mass of non­living jelly­lie (果冻状的) material and spread themselves over it.

    Larger transparent animals have the biggest challenge, because they have to make all the different tissues in their bodies slow down light exactly as much as water does. They need to look uniform. But how they're doing it is still unknown. One thing is clear for these larger animals, staying transparent is an active process.  When they die, they turn a non­transparent milky white.