How long has 3-D technology been around? Most of us might think of crowds of teenagers in a 1950's movie house watching Bwana Devil in 3-D. But 3-D technology made its first appearance on the scene in 1838 with the first stereoscope(体视镜). And the first actual 3-D movie was a 1903 film called Le Ariveed'un Train.

    Although it has such a long history, the technology has still remained based on one simple principle—to make 3-D effects you must find a way to project two slightly different pictures to each eye. Modern 3-D technology works by rapidly flickering(闪动)two versions of the movie and projecting them onto each eye. The brain does the rest of the work, combining the two pictures together into one and giving the show the appearance of depth, the third dimension.

    But does this exposure, especially long exposures, cause harm to the child's developing brain and visual system? Unfortunately, long-term studies on new flicker digital 3-D technology and children aren't yet available. We do not know if regular or daily 3-D viewing over years affects the developing visual system, although older 3-D methods basically do the same thing and are not considered harmful.

    The question of possible harm in modern 3-D use in TV is really based on two facts: the amount of time children will now be watching 3-D TV each day and the sensitivity some children show in reaction to 3-D viewing. It is difficult to make actual lab studies of longer term 3-D viewing in children because of the possible harm of the experiment. Researchers will have to wait until 3-D TV technology is already in the marketplace for a number of years, then check heavy 3-D TV watchers and compare them with non-watchers.

    With a 3-D television technology in the home, we will soon be able to answer the question of whether or not longer and more frequent periods of 3-D exposure cause more changes in the visual system. We may find that the bigger problem is the introduction of a new technology that leads to even more time spent on TV rather than playing outdoors.

    It was an oral English class and in front of us was standing our teacher Lila Betray, who was a university student from the US. Somehow we came to the point whether any of us could sing an English pop song in front of the class. You know, maybe three or more out of ten Chinese students are shy in class. As a result, there was silence in class for quite a while, which made everybody feel rather embarrassed(尴尬的), including the teacher.

    I was a shy boy. However, just at that moment, a great idea struck me suddenly."Seize the enjoyment! Seize the opportunity. Yes, there couldn't be a better opportunity." I said to myself. "Why not seize it? Why should I have always to be the guy regretting missing the opportunity just because of shyness? Yes, maybe I should have a try!"

    So, I raised my hand. And I remember that it took me quite a while to think what the song's name was. Though I sang no more than five sentences because of forgetting the lyrics(歌词), their clapping hands told me that I did the job well. Later, I got a gift and I was really happy.

    I think that is one of the most unforgettable moments in my life. Through this experience, I've also got to know that we should believe that we can do the job well, no matter how difficult it seems for us. Just have a little more courage.

    In Britain, many theatres put on shows for children at Christmas and many theatres have a theatre­in­education team working there. This team, made up of actors and teachers, writes plays for children, usually performing them in schools. They do different plays for different age groups and the children often take part in the play in some way.

    Pantomime is a special kind of Christmas show for children. It is loved by people and also allows the audience (观众) to join in.＂Pantomime＂ was the name of the Roman actor who performed shows without speaking — this is where the English word ＂mime＂ comes from.

    A pantomime is always based on a well­known children's story. But there are always certain types of characters in the show and certain situations and events. For example, a pantomime must always include a hero, known as the ＂principal boy＂ and this principal boy is always played by a pretty girl wearing a short costume (服装). Then there is the comic older woman, known as the ＂dame＂ who is played by a man. There is always a group of men and women who sing and dance and often there is a pantomime horse. The horse is played by two men who form the ＂front＂ and ＂back＂ ends inside a ＂horse＂ costume. It is funny and it usually kicks the dame when she isn't looking.

    Members of the audience have to shout a warning to one of the characters and argue (争论) with the character (usually the dame) when she does not believe them. When she shouts, ＂Oh no, it isn't, ＂ the audience always responds with ＂Oh yes, it is!＂ The audience also learns and sings a simple song and a few children are sometimes invited to help one of the characters during the show.

Three Feet From Gold

    Darby's uncle was caught by the “gold fever” in the gold-rush days, and went west to dig and grow rich. After months of labor, he was rewarded by the discovery of the shining ore (矿石). He needed machinery to bring the ore to the surface. So, with the “strike”, he returned home. And with the help of Darby, he borrowed a lot of money. After buying the machinery and having it shipped, Uncle and Darby went back to work the mine.

    The first car of ore was mined. And the returns proved they had one of the richest mines in Colorado! Down went the drills! Up went the hopes of Uncle and Darby!

    Then something happened! The vein (矿脉) of gold ore disappeared! They drilled on, but all in vain. Finally, they decided to quit and sold the machinery to a junk man for a few hundred dollars. The junk man called in a mining engineer to look at the mine and do a little calculating. The engineer's calculations showed that the vein would be found just three feet from where the Darbys had stopped drilling! The junk man took millions of dollars in the vein, because he knew enough to seek expert's advice before giving up.

    Most of the money which went into the machinery was borrowed through the efforts of Darby, who was then a very young man. The money came from his relatives because of their faith in him. He paid back every dollar of it, although he was years in doing so.

    Long afterward, Mr. Darby made another discovery that desire can be changed into gold. This discovery came after he went into the business of selling life insurance. Remembering that he lost a huge fortune, for he stopped three feet from gold, Darby profited by the experience in his chosen work, saying to himself, “I stopped three feet from gold, but I will never stop because men say 'no' when I ask them to buy insurance.”

    Darby sold more than a million dollars in life insurance annually. He owes his “stickability” to the lesson he learned from his “quitability” in the gold mining business.

    The koala is an unusual creature. Native to Australia and a bit bigger than a rabbit, it spends most of its time in eucalyptus trees（桉树）, feeding on leaves that are poisonous to nearly every other animal on the planet.

    The koala sleeps about 22 hours a day and spends the remainder of its time eating and resting. It might spend 10 minutes a day moving, experts say, usually from one tree to another. It has a soft pad at the end of its spine and extra thick fur on its rear end to make the effort, of sitting more comfortable.

    Threats and protective measures

    The unique lifestyle of the koala has helped it prosper, but today the cute and iconic creature is facing threats from habitat loss, disease and a changing climate. Koala populations are expected to decline by 50 percent in the next 20 years according to the Australian Museum.

    To help protect these animals, which bring in an estimated $1.1 billion to Australia each year through koala-related tourism, an international team of researchers has published the first complete genome（基因组）of the koala. Their hope is that the keys to the marsupial's（有袋动物）long-term survival might be planted in its genetic code.

"The ultimate goal is that we won't have to…rescue them from the edge of extinction," said Rebecca Johnson of the Australian Museum Research Institute in Sydney, who led the work.

    "Now we have a really good understanding of the koala genome, and we are in a fantastic position to use that knowledge to help us manage them."

    Early findings

    An elementary analysis of the koala's genome, published in Nature Genetics, has already yielded some interesting findings.

    For example, the authors found that, compared to other mammals, the koala's DNA includes an expansion in the number of genes that encode for enzymes involved in anti-poison. That allows them to have a diet that depends almost entirely on eucalyplus leaves which are unusually high in poison. However, it also means that koalas metabolize（代谢）medicines like anti-chlamydia antibiotics faster than other animals.

    The koala genome also revealed why koalas are such famously picky eaters. They are known to consume leaves from just 20 of Australia's 60 known eucalyplus species. And even when they are in one of their preferred trees, koalas take leaf selection very seriously.

    Information waiting to be discovered

    Johnson said that the information encoded in the koala's DNA is already being included in management strategies by conservation groups. However, she said the findings described in the new paper represent the early stages of what can be gleamed from the marsupial's genome.

    "The data is public, and I would love for anyone to start mining it and see what other amazing things they can find," she said." Once you have a genome of this quality, the sky's the limit with what you can do with it."

    All across the nation, in Americans' backyards and garages and living rooms, wild animals kept as pets live side by side with their human owners. It's believed that more exotic animals live in American homes than are cared for in American zoos. The exotic-pet business has drawn criticism from animal welfare advocates and wildlife conservationists alike, who say it's not only dangerous to bring wildlife into households but it's cruel and criminal. Yet the issue is far from black or white.

    The term exotic pet has no firm definition. It can refer to any wildlife kept in human households or simply to a pet that's more unusual than the common dog or cat. Privately owning exotic animals is currently permitted in a handful of states with no restrictions in America. Adam Roberts of Born Free USA keeps a running database of deaths and injuries caused by exotic-pet ownership: In Connecticut a 55-year-old woman's face was permanently disfigured by her friend's lifelong pet monkey; in Ohio an 80-year-old man was attacked by a 200-pound kangaroo；in Nebraska a 34-year-old man was strangled(勒) to death by his pet snake. And that list does not include the number of people who become sick from coming into contact with zoonotic(动物传染的) diseases.

    Some people see wild animals as pets as a way to connect with the natural world. Other exotic-pet owners say they are motivated by a desire to preserve threatened species. They believe climate change and human population growth could wipe out a species in record time, so having a backup population is a good idea.

    But some groups like Born Free USA and the World Wildlife Fund say that captive breeding(圈养) of endangered species by private owners—whether for commercial, conservation, or educational reasons—serves only to continue a booming market for exotic animals. That, in turn, results in a greater risk to animals still living in their natural habitat.