Almost every machine with moving parts has wheels, yet no one knows exactly when the first wheel was invented or what it was used for. We do know, however, that they existed over 5,500 years ago in ancient Asia.

    The oldest known transport wheel was discovered in 2002 in Slovenia. It is over 5,100 years old. Evidence suggests that wheels for transport didn't become popular for a while, though. This could be because animals did a perfectly good job of carrying farming tools and humans around.

    But it could also be because of a difficult situation. While wheels need to roll on smooth surfaces, roads with smooth surfaces weren't going to be constructed until there was plenty of demand for them. Eventually, road surfaces did become smoother, but this difficult situation appeared again a few centuries later. There had been no important changes in wheel and vehicle design before the arrival of modem road design.

    In the mid-1700s, a Frenchman came up with a new design of road—a base layer (层) of large stones covered with a thin layer of smaller stones. A Scotsman improved on this design in the 1820s and a strong, lasting road surface became a reality. At around the same lime, metal hubs (the central part of a wheel) came into being, followed by the pneumatic tyre(充气轮胎) in 1846. Alloy wheels were invented in 1967, sixty years after the appearance of tarmacked roads (柏油路). As wheel design took off, vehicles got faster and faster.

    Let's face it. No one drinks diet sodas for the taste. People drink diet sodas in the hope that it will help them lose weight or at least keep them from gaining it. Yet it seems to have exactly the opposite effect, according to a new study.

    Researchers from the University of Texas said those who drank two or more diet sodas a day had waist size increases that were six times greater than those who didn't drink diet sodas. ＂What we saw was that the more diet sodas a person drank, the more weight they were likely to gain,＂ said Sharon Fowler.

The study was based on data from 474 participants in a large, ongoing research project, where the participants were followed for nearly 10 years.

    While the findings are surprising, they also offer some explanations.

    Nutrition expert, Melanie Rogers, who works with overweight patients in New York, has found that when patients are switched from regular to diet sodas, they don't lose weight at all. ＂We weren't seeing weight loss necessarily, and that was confusing to us,＂ said Rogers.

    So why would diet soda cause weight gain? No one knows for sure yet, but it could be that people think they can eat more if they drink diet sodas, and so over-compensate for the missing calories.

    A related study found some sweeteners (甜味剂) raised blood sugar levels in some mice. ＂Data from this and other potential studies suggest that the promotion of diet sodas and artificial sweeteners may be risky,＂ said Helen P. Hazuda, professor at the University of Texas's school of medicine. ＂They may be free of calories, but not of consequences.＂

    She was returning from teaching out in a small community. It was a black, moonless night, and a heavy snow was falling.

    She thought back to the time when she had first started teaching out in small communities. During those days she had always picked up hitchhikers (搭便车者), until the day her sister told her that one of her friends had been shot in the head by a hitchhiker, all because she had stopped out of kindness to help him during a storm.

    Her family didn't stop worrying about her safety over the hitchhikers until the family heard the promise: “No more hitchhikers!” The snow that night was making her think back to this.

    Then she saw a man waving. She slowed down for him, but as he ran toward the car in the dark, she shook with fear. Yet she thought that if he was truly in need, she couldn't leave him here in this storm.

    The stranger explained that his car was dead, and she told him to get in. They drove for an hour into the next city and she took him to a convenience store. She waited until he had made a call. When he reported back to her that a family member would soon come to pick him up, she wished him well and then left.

    Tears fell on her cheeks as she drove away. It felt as though she had been holding her breath for an hour.

    “I hope they'll understand why I had to break my promise,” she thought.

    Japanese technology giant Toshiba has built a huge "clean" factory farm where it is growing various types of lettuce (莴苣) leaves without sunlight or soil for sale in its new healthcare business.

    Located in a disused 21,000­square­foot electronics factory in Yokosuka, Toshiba announces to have created a perfect "bacteria­free" environment where it will grow three million bags of lettuce a year.

    Completely cut off from conditions outside the temperature controlled tank, lettuce inspectors wear full body suits while making notes on the quality and growth of the leaves on their iPads in order to prevent the air around the plants becoming contaminated.

    Each plant is given man­made lighting to trick it into believing it is exposed to sunlight, while vitamin and nutrients are put directly into its roots, meaning the lettuce does not need soil.

    Toshiba's new high­tech farm may produce the world's highest quality lettuce. The final product will be free of any form of bacteria or insect life before being placed into sealed (密封的) bags, which should ensure the product has a longer shelf life than other lettuces.

    The gardening technique aims to have a bacteria amount of no more than 1/1000th­much lower than that found in normal gardening soil.

    Toshiba aims to harvest three million bags of leaf lettuce, baby leaf greens, cabbages and other kinds of vegetables every year­with each bag likely to cost people £1.

    The most important thing in organic vegetables, the lettuce requires no pesticides (杀虫剂) but is expected to have a similar shelf to plants that have been heavily treated with chemicals.

    The lettuce factory is no marketing trick by Toshiba, however. Instead it represents the company's latest attempt to expand its technology­led business.

    There are already plans for the technology giant to build similar factories around the world over the coming years and it will also be selling the high tech equipment that allows factories to produce similar products of exceptionally high quality.

    When we are young we are taught that it's wrong to lie and we should always tell the truth. Unfortunately, most children lie even if they're told not to. Research carried out at the Institute of Child Study at Toronto University has shown that this might not be such a bad thing. Apparently (显然地), children who tell lies when they're two years old have a good chance of becoming successful adults (成年人).

    According to the research, at the age of two, 20 percent of children lie. At the age of three, 50 percent lie, and at four almost 90 percent lie. By the age of 12 almost every child tells lies.

    Lying needs much brain work. And the better the lie is, the more work the brain has to do. By training the brain early, researchers believe children will be able to think more clearly when they are adults.

    Recent research, carried out by the Science Museum in London, has shown some interesting facts about the way we lie as adults. According to the research, the average British man tells three lies every day, that's over 1,000 lies a year. However, the average woman apparently only lies twice a day.

    Most people think women are better liars (说谎者) than men although in fact they tell fewer lies. Popular women's lies include 'Nothing's wrong, I'm fine', 'I don't know where it is, I haven't touched it', and 'It wasn't that expensive'.

    Some people say you can lie as long as it's a white lie. A white lie is a lie told to avoid hurting someone's feelings. One of the most common lies for both men and women is 'It's just what I've always wanted', said after opening a present from their partner.

Tales From Animal Hospital David Grant

    David Grant has become a familiar face to millions of fans of Animal Hospital. Here Dr Grant tells us the very best of his personal stories about the animals he has treated, including familiar patients such as the dogs Snowy and Duchess, the delightful cat Marigold Serendipity Diamond. He also takes the reader behind the scenes at Harmsworth Memorial Animal Hospital as he describes his day, from ordinary medical check-ups to surgery. Tales From Animal Hospital will delight all fans of the program and anyone who has a lively interest in their pet, whether it be cat, dog or snake!

    £14.99 Hardback 272pp Simon Schuster

    ISBN 0751304417

    Isaac Newton: The Last Sorcerer Micheal White

    From the author of Stephen Hawking: A Life in Science, comes this colorful description of the life of the world's first modern scientist. Interesting yet based on fact, Michael White's learned yet readable new book offers a true picture of Newton completely different from what people commonly know about him. Newton is shown as a gifted scientist with very human weaknesses who stood at the point in history where magic ended and science began.

    £18.99 Hardback 320pp Fourth Estate

    ISBN 1857024168

     Fermat's Last Theorem Simon Singh

    In 1963 a schoolboy called Andrew Wiles reading in his school library came across the world's greatest mathematical problem: Fermat's Last Theorem ( 定 理 ). First put forward by the French mathematician Pierre de Fermat in the seventeenth century, the theorem had baffled and beaten the finest mathematical minds, including a French woman scientist who made a major advance in working out the problem, and who had to dress like a man in order to be able to study at the Ecole Polytechnique. Through unbelievable determination Andrew Wiles finally worked out the problem in 1995. An unusual story of human effort over three centuries, Fermat's Last Theorem will delight specialists and general readers alike.

    £12.99 Hardback 384pp Fourth Estate

    ISBN 1857025210