A brain can also simply be a smartperson,  If a person is called brainy,she is smart and intelligent. If a family has many children but one ofthem is super smart, you could say, "She's the brains in the family. "And if you are the brains behind something you are responsible for developing or organizing something. For example, Bill Gates is the brains behind Microsoft Brain trust is a group of experts who give advice. Word experts say the phrase "brain trust" became popularwhen Franklin D. Roosevelt first ran for president in 1932, Several professors gave him advice on social and political issues facingthe U.S.

    These professors were called his "braintrust." These ways we use the word"brain" all make sense. But other ways we use the word are not so easy to understand. Forexample, to understand the next brain expression, you first need to know theword “drain." As a verb to drain means to, remove something by letting it flow away. So abrain drain may sound like a disease where the brain flows out the ears. But, brain drain is when a country's most educated people leave their countries to live in another. The brains are, sort of, draining out of the country.

    However, if people are responsible for agreat idea, you could say they brainstormed it. Here, brainstorm is not an act of weather. It is a process of thinking creatively about a complex topic. Forexample, business leaders may use brainstorming to create new products, and government leaders may brainstorm to solve problems.

    If people are brainwashed, it does notmean their brains are nice and clean. To brainwash means to make someone accept new beliefs by using repeated pressure in a forceful or tricky way. Keep inmind that brainwash is never used in a positive way.

    Renowned British physicist Stephen Hawking died peacefully at his home in the British university city of Cambridge in March 14 at age 76.

    Hawking, whose 1988 book “A Brief History of Time” became an unlikely worldwide bestseller and cemented (奠定) his superstar status, dedicated his life to unlocking the secrets of the Universe. He held the post of Lucasian Professor of Mathematics at the University of Cambridge, which is a position that was once held by Sir Isaac Newton.

    Born in 1942 in Oxford, where his parents spent the final months of pregnancy to avoid the bombings of London, Hawking was said to have been a good student although it wasn't until he was in his 20s that his true potential began to really shine through. Having initially wanted to study Mathematics, Stephen Hawking chose, instead, to read natural sciences with emphasis on Physics.

    Having found University life boring, so much so that he joined the University rowing team to relieve the boredom, it was only following an oral examination that he was awarded a first class degree.

    While at Cambridge, Hawking was diagnosed with a motor neurone (神经元）disease. He was initially given two to three years to live. The illness gradually robbed him of mobility, leaving him confined to a wheelchair, almost completely paralysed and unable to speak except through his trademark voice synthesiser (合成器）.

    Stephen Hawking led an incredible and well documented life. He was referred to in many TV programs, films, and even songs, and appeared as himself in a number of programs including Red Dwarf and the Big Bang Theory. His genius and wit won over fans from far beyond the world of astrophysics (天体物理学）, earning comparisons with Albert Einstein and Sir Isaac Newton.

    As an expert on the science of sleep and sleep disorders, Michael Twery believes “People have good understanding about the necessity of sleeping 7-8 hours in bed. But they undervalue the function of napping in day.”

    For example, many Americans do nap. But one-third of adults in the US are also frequently tired. Someone who naps as a way of paying off a sleep debt may not experience the same improvements from napping as a healthy, well-rested person would.

    Also, many people may not want to admit that they take a nap. That only children, the very old, sick or lazy people nap is a common opinion. In fact, Americans sometimes do very strange things. For those who claim they only sleep five hours a night, they may think they are somehow stronger than the average human—superhuman, if you will.

    Luckily, many offices now offer napping rooms in many U. S. cities. While resting in the middle of the work day may seem like a luxury to Americans, napping is very much part of a normal, everyday life in other parts of the world.

China, generally speaking, is a land of nappers. Researchers recently looked at information provided by nearly 3, 000 Chinese adults, aged 65 years or older. Based on their answers, researchers put them into four groups: non-nappers (0 minutes), short nappers (less than 30 minutes), moderate nappers (30-90minutes), and extended nappers (more than 90 minutes).

    The study found that the hour-long nappers did better on the tests than those who napped for shorter and longer periods. Keep in mind, however, that these are the findings for those over the age of 65.

    Michael Twery notes that an hour long nap may be too long for young, healthy adults. “Currently, 30 minutes is enough to remove the pressure to sleep and will help us feel more awake. If we nap longer, we will get trapped into sleep inertia—a very deep sleep period.”

    For centuries people have hunted animals for food and pleasure.The invention of the gun made it so easy for humans to hunt that some animals were lolled by the thousands and even became extinct（绝种的）.This brings up some serious problems since breaks in the food chain upset the balance of nature.

    Large animals like tigers are being killed by the hundreds every year in India.The Royal Bengal tiger is the only type that exists in India and their number is greatly reduced every year because of poaching（偷猎）.The present number is about 2,000, all of which live in tiger reserves.Two hundred years ago the population was 23,000 or more.

    During the British rule of India,many of the so-called English gentlemen killed tigers for pleasure and to show their bravery.This seems stupid because killing an innocent（无辜的）creature with a gun is not a brave deed.

    Today the tiger skin is very popular.Rich people and fashion designers have no idea what they are doing. Competition between the rich to show off makes them blind to the serious effects.People persuade villagers to kill tigers to get money,and they do it because they are poor and need to feed their families.We must educate them,and the government should give them proper jobs to help solve this problem.

    The people to blame are those who buy animal products like ivories,furs,tiger bones for medicine and handbags made of animal skins.They must be put behind bars to stop this kind of trade.The earth is home for everyone on it. The trees,animals,birds,and fish of all kinds belong here as much as we do.Only we have the power to change their fate.

    A Chinese scientist's attempt to produce the world's first gene-edited babies who are immune to HIV has caused floods concern.

    In an online video posted on Monday, He Jiankui, a biological researcher, announced that a pair of twin baby girls, Lulu and Nana, was born healthy a few weeks ago with genetic editing technology that can prevent them from being infected with HIV.

    He, who was believed to be in Hong Kong on Monday to attend the Second International Summit on Human Genome Editing, could not be reached for comment. But his announcement sparked a heated argument concarning medical ethics（伦理）and effectiveness.

    The Shenzhen Health and Family Planning Commission said on Monday evening that it had not received any ethical assessment application for the study, which is required as a prior condition for such experiments.

    More than 120 scholars from universities and institutes with high status from China and abroad,such as Tsinghua University and the Massachusetts Institute of Technology (MIT),strongly condemned the research in a signed statement, saying the “research” lacks effective ethics inspection, and it amounts to human experimentation,which is “crazy”.

    In the statement, published on Sina Weibo, the scientists said any attempt to make changes to human embryos with genetic editing and give birth to such babies involves high risk as an inevitable part, due to inaccuracies in existing genetic editing technologies.

    “Scientists all over the world dare not make such attempts due to the huge risks and more importantly, ethics. The government must make quick legal moves to strictly supervise（监督）such research. The Pandora's Box has been opened, and we may still have a chance of closing it before it is too late,”the statement said.

    Tsui Lap-chee, president of the Academy of Sciences of Hong Kong, said a lot of issues may occur in gene editing. If one gene is edited, it will affect others that interact with it. And the whole genome, a collection of genes, may also be affected.

    They're in restaurants, hotels and homes all over the world. The saltwater aquarium, with its colour fish, bring a piece of the wild into your living room.

    But do you really know where those saltwater fish come from? A full 97 percent, yes, almost all kinds of saltwater fish can't be bred in captivity (人工养殖). They must instead be taken from the ocean. And how is that done?

    Most of the time, with sodium cyanide, it is a harmful chemical compound that many fish collectors in the Philippines, Sri Lanka, and Indonesia use to catch fish. They mix it with water and use it on the fish. Stunned, the fish can then be easily caught.

    What does cyanide do to the fish? There is a scientific study on cyanide's effects. When there is cyanide in water, fish lose their balance and have difficulty breathing. Some fish simply die then and there. Many, many more die on the way to captivity.

    Although cyanide fishing in the Philippines, Sir Lanka, and Indonesia is not allowed, it still happens too often. According to the World wildlife Fund, up to 90 percent of the saltwater fish that enter the US each year are caught this way. The Center for Biological Diversity is calling on the US government to avoid these imports.

    “Compared to many environmental problems now facing the world's oceans, this is one that can easily be solved,” said Nicholas Whipps of the Center. “Because the US is such a powerful market player in this industry, the responsibility to stop this practice falls largely on the United State' shoulders.”

    In the Philippines, private planes bring in cyanide to the fisherman and then take away the live fish. Live fish give the fisherman a better life than dead ones, so more and more fishermen have turned from supplying the fish-for-food trade to the fish-for-aquariums trade.

    The Center for Biological Diversity hopes the government will use the law to turn away cyanide-caught fish and persuade people to buy those only raised in captivity.