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 see-through? 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 see--through. Others build a large, clear mass of

 non-living jelly-lie(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 non-transparent milky white.

    With the summer holiday just around the corner, it seems like everybody is busy planning their vacations. Here are some tips that can help you enjoy your holiday without empting your pocket:

    Travel off-season

    Go to your desired destination while the demand is low and take advantage of huge discounts. During the peak season, the hotel and flight prices increase quickly, and you'll likely spend more of your vacation time standing in line due to the rush of tourists. {#blank#}1{#/blank#}

    {#blank#}2{#/blank#}

    Websites can help you find discount hotel rooms. Look for places that do not charge extra for children if they use the existing bedding. Stay with the locals. If you and your family are going to stay for a longer period, renting a small apartment is a good choice.

    Eat like a local

    Why eat at big chain restaurants when you can experience something new? {#blank#}3{#/blank#} During your family trip, try new food where the locals eat. This will not just save money, but also provide you with a new and different experience. For smaller meals and snacks, avoid restaurants and try street food or other takeout. 

    Don't hesitate to bargain

    Tourist- heavy places are known for overcharging for just about everything. Clothes, travel goodies, souvenirs, etc. are very expensive at these places. {#blank#}4{#/blank#} Bargain hard to get the best price.

    Choose local transportation

    {#blank#}5{#/blank#} Instead, take buses, railways or subways, which are always cheaper. If you are planning to stay for a while, you can consider renting a car. Hiring a car is much easier than carrying your bags everywhere if you are moving around a lot.

A. Save on hotels.

B. Surf the Internet while traveling.

C. Therefore, avoid buying anything there.

D. So it's best to find out when the off-season starts.

E. Planning your meals is another way to reduce your travel costs.

F. For this reason, you shouldn't feel ashamed to ask for bargains.

G .As a tourist, avoid taking taxis whenever possible, since they are expensive.

    Bats are the only mammals(哺乳动物) that can fly a great distance, but they have another ability. Many bats live a very long time for an animal of their size. European researchers are studying bats to understand why they lives0 long. They hope to make discoveries aimed at fighting the aging process in human beings.

    Last week, the group of scientists said they had identified important biological qualities in some bat species. The group studied bat chromosomes(染色体), a line of genes found in the nucleus(细胞核) of cells. The scientists were most interested in structures connected to the ends of the chromosomes. They are called telomeres(端粒), which protect the ends of chromosomes and shorten each time a cell divides. Scientists believe this shortening process causes cells to breakdown. They say this is what causes aging.

    The European researchers studied 493 bats from four bat species. The group used information that had been gathered over more than 60 years. Of these animals ，the greater mouse-eared bat generally lived the longest, an average of 37 years. The scientists said this and a related species, which are grouped together under the name Myotis, had telomeres that did not shorten with age. Another Myotis bat holds the record for oldest age, reaching 41years. The scientists' findings suggest that these bats cells have the ability to maintain and repair their telomeres. This, they said, helps guard against the aging process.

    Based on its body size, a bat like the greater mouse-eared bat would be expected to live four years. But, these mammals have been found to live nearly 10 times longer than that. The scientists found that only 19 species of mammals live longer than humans when their body size is considered. Eighteen of these are bats.

    The softshell turtle species is officially listed as endangered by the IUCN Red List. Scientists long thought softshell turtles were extinct in the Cambodian part of the Mekong River until they discovered some stragglers (掉队者) in the early 2000s.

    The species had quite a wide historical range across Asia, but much of that range is now completely gone. Much of the turtle's habitat in Southeast Asia have disappeared due to urban and industrial development along the Mekong River. The sand where turtles multiply is routinely carried away for use in construction projects, while fishing nets lift up hatchlings. People also take turtles and their eggs to sell for food.

    Initial surveys in 2003 and in 2007 found two small populations of the softshell turtles along a 30-mile stretch (水域) of the Mekong River. Since then, conservation groups have worked with local communities and officials to increase the wild population of these endangered turtles, including a program to hire former egg collectors to help search for and protect nests instead of harvesting the eggs.

    For the last decade, WCS, Conservation International, the Turtle Survival Alliance and local groups have worked to protect turtle nests. Their goal is to ensure eggs will multiply and hatch, and that baby turtles grow strong enough to eventually take care of themselves in the wild.

    A team recently released 150 hatchlings back into their natural habitat, bringing the total to more than 7,700 baby turtles in the past 10 years.

A Lesson Plan from Life Planning Education: A Youth Development Program

    Purpose: To learn about body language and how to use body language.

    Materials (材料): Cards; container

    Time: 25-35 minutes

    Planning Notes:

    ·Write the words below on cards:

    angry disappointed shy afraid sad happy nervous excited bored

    ·Place the cards in the container so volunteers can draw them out one at a time.

    Steps:

    First make sure that all volunteers know what body language means (expressing feelings through body movement and facial expressions). Go over the following instructions:

    ·I'll need at least 9 volunteers to play a game similar to charades (猜词游戏).

    ·The first volunteer will draw a card with a feeling written on it and act out the feeling without using words.

    ·The rest of the group will guess what feeling is being communicated. Once someone correctly guesses the feeling, the next person in line will draw a card and act out what is written on it, again without words.

    ·The game will continue until there are no more cards or until time is up.

    At last, end the activity using the discussion points below:

    ·Can you give examples of when someone's body language communicated a different message from what he/she actually skid?

    ·Sometimes one person is offended (冒犯) by another's body language. How can you work to keep that from happening? Answers may include: be honest and direct; match your nonverbal messages to your verbal ones; be aware of (清楚) cultural attitudes toward different kinds of body language.

    When I was growing up, we were not an "I love you" family. We certainly found such affection lovely. We just didn't do it.

    I was thinking about all of this on Saturday at my daughter Katie's recital (演奏会). I had never insisted she do anything in her free time except learn how to play the piano. I carried this from childhood. My parents couldn't afford these lessons. My daughter mostly accepted this demand with good humor. This has meant, through the years, that our house has been filled with a few muddled (混乱的) complaints mixed with versions of songs.

    The day of the recital, I was listening to Katie practice The Entertainer, and one note was not good. I don't know how to play the piano, but I did say, "Hey, Katie, maybe you should hold that note just a bit longer." Then she played it again and again. I realized that I had done something unintended — I was making her think too much just a few hours before her recital.

    So I told her not to worry about it, but it was too late. She kept at it for a little while longer until finally I said that she'd played it perfectly. I didn't think we ever isolated that note; I felt pretty bad for even bringing it up.

    Then it was time for recital. Katie was the first one to perform. She was dressed well. As I watched her play The Entertainer, all I could think was how grown-up she had become, and that I had already missed the four-, five-, six-year-old versions of her.

    She got to the end of the song, and she reached the note we had talked about. And she held it. She held it so long that for an instant it broke her timing on the rest of the song. Then she finished the song, and she looked right at me. Then I hugged her. My parents are right. You don't have to say the words "I love you". Sometimes one note will do.