If you could change your child's DNA in the future to protect them against diseases, would you? It could be possible because of technology known as CRISPR-Cas, or just CRISPR.

    CRISPR involves a piece of RNA, a chemical messenger, designed to work on one part of DNA; it also uses an enzyme (酶) that can take unwanted genes out and put new ones in, according to The Economist. There are other ways of editing DNA, but CRISPR will do it very simply, quickly, and exactly.

    The uses of CRISPR could mean that cures are developed for everything from Alzheimer's to cancer to HIV. By allowing doctors to put just the right cancer-killing genes into a patient's immune system, the technology could help greatly.

    In April scientists in China said they had tried using CRISPR to edit the genomes (基因组) of human embryos. Though the embryos would never turn into humans, this was the first time anyone had ever tried to edit DNA from human beings. With this in mind, the US' National Academy of Sciences plans to discuss questions about CRISPR's ethics (伦理问题).

    For example, CRISPR doesn't work properly yet. As well as cutting the DNA it is looking for, it often cuts other DNA, too. In addition, we currently seem to have too little understanding of what DNA gives people what qualities.

There are also moral questions around “playing God”. Of course, medicine already stops natural things from happening —— for example, it saves people from infections. The opportunities to treat diseases make it hard to say we shouldn't keep going.

    A harder question is whether it is ever right to edit human germ-line (种系) cells and make changes that are passed on to children. This is banned in 40 countries and restricted in many others. However, CRISPR means that if genes can be edited out, they can also be edited back in. It may be up to us as a society to decide when and where editing the genome is wrong.

    Also, according to The Economist, gene editing may mean that parents make choices that are not obviously in the best interests of their children: “Deaf parents may prefer their children to be deaf too; parents might want to make their children more intelligent at all costs.”

    In the end, more research is still needed to see what we can and can't do with CRISPR. “It's still a huge mystery how we work,” Craig Mello, a UMass Medical School biologist and Nobel Prize winner, told The Boston Globe. “We're just trying to figure out this amazingly complicated thing we call life.”

    Tom Costello was once afraid of homeless Americans. “I was so afraid that if I saw a homeless person walking down the street, I'd cross the street,” he said.

    That changed seven years ago after his wife, Nancy, a volunteer at a homeless shelter, persuaded him to help with a holiday dinner for shelter residents. Tom remembered going to a store and buying socks for the residents. He knew many of them were in need of clothing.

    At the shelter, Tom said, he dropped a pair of socks into a bag for a woman. She asked him if she could have socks for a friend who wasn't with her that day. He gave her another pair. “She started to cry and told me that nobody had ever given her socks before,” Tom said, “Then she reached out and gave me a hug.” That experience at the shelter helped Tom end his fear of the homeless.

    It also led him to set up a group called “The Joy of Sox.”, which borrows from a name of a popular book. The group collects socks from donors and gives them mostly to shelters in the area where Tom and Nancy live. It has been expanding its reach and provides socks to homeless shelters in 21 states and other three countries now.

    Why socks? Tom explains that some Americans give food, coats and other clothing to shelters. But donating socks is not something most people think about. And, he said, socks are very helpful at keeping people warm, especially in cold weather. A man named Kiwi，who has lived in homeless shelters, said most of the time he could find enough food through shelters and soup kitchens. But socks were much more difficult to get, he noted.

    Here is a list of some of the best museums for children in America.

    Please Touch Children's Museum

    This museum lies in Philadelphia. It offers Alice in Wonderland exhibits where young children can play with giant flowers and have tea parties. Kids can also play on musical instruments and babies can crawl on lily pads, which make musical sounds.

    The Children's Museum of Indianapolis

    This museum lies in Indiana. It holds a fair share of dinosaur fossils (化石). There are many fossils like the T. Rex, Bucky and many others in an 8,000-square-foot area. Around 10,000 man-made objects, including a 55-ton steam engine and a 33-foot tall water clock, are there in the 365,000-square-foot area. It also offers activities like dinosaur building, camps and classes featuring space themes and other educational programs.

    Boston Children's Museum

    This museum lies in Massachusetts. The exhibits here are of health, art, science, culture and environment. In this museum, children also learn about Japanese culture. Activities like Play Lab, New Balance Climb and The Recycle Shop bring out the creativity in children.

    National Museum of Play

    This museum, which lies in Rochester area of New York, has a wide collection of dolls, games, toys and other home crafts dating back to the 19th century. Here, educational tours include stories of machines and other toys. Kids can walk in Sesame Street exhibit and cook food at play or TV studios.

    Children's Museum of Houston

    This museum lies in Texas. Termed as the best playground for mind, this museum offers scores of activities for kids of every age. It even offers free family adventure events where families with their kids are encouraged to work on math activities and games. Children also learn about broadcasting activities and preserving ecosystems.

    The Lumière Brothers had their film shows, taken over 100 years ago, to 100 paying customers on December 8, 1985. One of their earliest films was a 30-second piece which showed a section of a railway platform. As the train approached, panic started in the theatre: people jumped and ran away. In their confusion, the audiences feared that a real train was about to crush them. That was the moment when cinema was born.

    Early cinema audiences often experienced the same confusion. In time, the idea of films became familiar, the magic was accepted — but it never stopped being magic. Film has never lost its unique power to embrace its audience and transport them to a different world.

    One effect of this realism was to educate the world about itself. Cinema makes the world smaller. Long before people travelled to America or anywhere else, they knew what other places looked like and how other people worked and lived. Undoubtedly, in the lives recorded in film people knew more about American life. Hollywood has dominated the world film market. American imagery — the cars, the cities, the cowboys became the primary imagery of film. Film carried American life and values around the globe.

    And, thanks to film, future generations will know the 20th century more familiarly than any other period. We can only imagine what life was like in the 14th century or in classical Rome. But the life of the modern world has been recorded on films. We shall be known better than any preceding generations.

    The “star” was another natural consequence of cinema. The cinema star was effectively born in 1910. Because everybody in the world seems to know who they are, they appear more real to us than we do ourselves. The star as magnified human self is one of cinema's most strange and enduring legacies(遗产).

    Cinema films originally were planned as short stories, because early producers doubted the ability of audiences to concentrate for more than the length of a reel. Then, in 1912, an Italian 2-hour film was hugely successful, and Hollywood settled upon the novel-length narrative that remains the dominant cinematic convention of today.

    And it has all happened so quickly. Almost unbelievably, it is only 100 years since that train arrived and the audience screamed and fled, perhaps, suddenly aware that the world could never be the same again — that, maybe, it could be better, brighter, more astonishing and more real than reality.

    American and British people both speak English of course. But sometimes it does not seem like the same language. In fact, there are some important differences between British English and American English.

    First of all, they sound very different. Often, Americans don't say each word separately. They say several words together. Americans may say "I dunno" instead of "I don't know". Or they may say "Whaddaya say?" instead of "What do you say?" However, the British are more careful in their speech. They usually say all the words and keep them separate.

    Sound is not the only difference between British English and American English. Words sometimes have different meanings too. Some American words are never used in England. The same thing is true of some British words in America. For example, the vocabulary for cars and driving is very different. Americans drive trucks, but in England people drive lorries.

    Many expressions are also different in the two countries. In England，if you are going to telephone your friends, you "phone them up". In America, you "give them a call". When you are saying goodbye in England you might say "Cheerio!" In America you might say "See you later."

    There're also some differences in grammar. For example, Americans usually use the helping verb "do" when they ask a question. They say "Do you have a storybook?" But the British often leave out the helping verb. They say "Have you a storybook?"

    All these differences can be confusing if you are learning English. But most languages are like this. Languages change over time. When people live in separate places, the languages change in different ways. This is what has happened to English. It can also happen to other languages, such as French. Many people in Canada speak French, but their French is very different from the French of France.

Families with unhealthy diets have worse mental health than those who mostly avoid meals packed with sugar, fat and salt. A new study is the first to show that children's mental health is not immune to what they eat, especially inflammatory (引起炎症的) diets.

The effects of inflammatory diets are putting kids on a path to poor mental health from as young as age 11. The evidence (证据) is now well proved that inflammation in the body is actually damaging bodies gradually and leading to many chronic (慢性的) diseases.

The Murdoch Children's Research Institute (MCRI) looked at the diets and self-reported mental health of more than 1,800 Australian parents and their 11-to-12-year-old children. as well as measuring markers of chronic inflammation in their blood.

The study, published in the British Journal of Nutrition, showed the benefits of healthy eating—namely anti-inflammatory diets high in fruit and vegetables—extended beyond physical health, and that families can eat their way to good mental health.

A child's weight was not an influencing factor. Regardless (不管) of size, the bad effects of inflammatory diets high in processed foods affected children across the board.

Lead researcher at the MCRI, Dr Kate Lycett said while research had shown that specific anti-inflammatory diets could reduce depression symptoms (症状) in adults, people knew little about the effect on children and how a typical family diet—a mix of both inflammatory and anti-inflammatory foods—affected mental health.

"What surprised me was we saw the same results in terms of the risk in children and parents," Dr Lycett said. "That's really important, because as adults we try to control what we eat. We know when we eat a packet of chips we feel sad, but we often don't think about that when we give our kids those chips."