Grown-ups are often surprised by how well they remember something they learned as children but have never practiced ever since. A man who has not had a chance to go swimming for years can still swim as well as ever when he gets back in the water. He can get on a bicycle after many years and still ride away. He can play catch and hit a ball as well as his son. A mother who has not thought about the words for years can teach her daughter the poem that begins "Twinkle, twinkle, little star" or remember the story of Cinderella or Goldilocks and the Three Bears.

    One explanation is the law of overlearning, which can be stated as follows: Once we have learned something, additional learning trials increase the length of time we will remember it.

    In childhood we usually continue to practice such skills as swimming, bicycle riding, and playing baseball long after we have learned them. We continue to listen to and remind ourselves of words such as "Twinkle, twinkle, little star" and childhood tales such as Cinderella and Goldilocks. We not only learn but overlearn.

    The multiplication tables(乘法口诀表) are an exception to the general rule that we forget rather quickly the things that we learn in school, because they are another of the things we overlearn in childhood. The law of overlearning explains why cramming (突击学习) for an examination, though it may result in a passing grade, is not a satisfactory way to learn a college course. By cramming, a student may learn the subject well enough to get by on the examination, but he is likely soon to forget almost everything he learned. A little overlearning, on the other hand, is really necessary for one's future development.

    Wild mangoes come from the foothills of the Himalayas. They are by far the most important fruit in India, and have been cultivated there for four thousand years. The arrival of the mango tree in other parts of the world was probably due to the Portuguese who carried mangoes via Goa to Africa, from where they eventually reached the New World. Mango trees are now so well established in many tropical countries that it might appear that they have always been there.

    Like many tropical trees, the mango tree is multi-purpose product. Its wood is used in boat building, and its leaves can be fed to cattle. Most of the mango crop is consumed in the areas where it is grown, but in recent years mangoes have gained in popularity across the world as people in mild climate become increasingly eager to enjoy the delight of the fresh fruit.

    The global market for mangoes is very profitable, and mango producers are keen to make use of the fruit's growing popularity. Modern shoppers not only appreciate the fruit's high nutritional value(the mango is a good source of vitamin A and C, protein and fibre), but also expect it to look and taste perfect. Therefore producers now select only the best quality seedlings which have the most chance of developing into good quality fruit.

    Mangoes are high in fiber, thus making them very good for the heart. The high fiber content is also helps easing constipation. They have high pectin(果胶) and vitamin C content that reduces the blood cholesterol levels and serves as an immune booster. This fruit is rich in anti-oxidants, vitamins, minerals and contain an enzyme(酶) that has stomach soothing properties. These enzymes act as a digestive aid and digestive proteins.

    Although the mango tree has spread from its native Himalayan foothills to the tropics, delivering the fresh fruit to the world's supermarkets presents a challenge, as it does not travel well. Producers transport the fruit by speedy but costly air freight (货运)for minimum delay rather than risk the cheaper but slower road or shipping routes which, can result in damage to the fruit.

    Mangoes are usually in storage for some time after their arrival at their destination. The fruit must be kept cold, or the sweet, juicy flesh will soon become over ripe and the mangoes will be unfit for sale. Fortunately, extremely effective refrigeration is now available and this is the best way of preventing the fruit from going bad before it reaches the supermarket shelves.

    Choosing where to live may be one of the biggest decisions you'll make when you move to Sydney, but you'll have plenty of help.

    Temporary arrival accommodation

    Before you move to Sydney, we recommend that you book a temporary place to stay. Once you get here, you can look for longer-term accommodation.

    --sydney.edu.au/accommodation/short-term

    On-campus-residential colleges (fully catered饮食全包的)

    The University has eight residential colleges on the Camperdown/Darlington Campus, including International House, a residential community of global scholars. Colleges provide comfortable, fully furnished single rooms and daily meals, along with sporting, cultural, leadership and social programs. They also include on-site tutorials(辅导课) in addition to campus-based classes.

    --sydney.edu.au/colleges

    On-campus residences (self-catered饮食自理的)

    The University has two self-run residences—Queen Mary Building (QMB) and Abercrombie Student Accommodation—on the Camperdown/Darlington Campus. Both just under a year old, they house up to 1000 students. These residences provide modern single-study rooms with large common living, learning and study spaces, shared kitchens, a theatre, gyms, soundproofed music rooms, art studios, sky lounges and rooftop gardens.

    --sydney.edu.au/campus-life/accommodation/live-on-campus.html

    Off-campus living

    More than 90 percent of our students live off campus. The University is close to many dynamic and multicultural suburbs such as Annandale, Newtown, Chippendale and Glebe. A great place to search is our large online database of properties.

    --sydney.edu.au/campus-life/accommodation/live-off-campus.html

    Robert is a boss who hires me as a helper.He has lost his house and now has to live back at home,with his mother,at 46.

    We had a job in Fort Bending.Robert bought me breakfast there.As we were leaving,a man walked to us asking if he could get some work from Roberts' company.Robert explained there was no work for the man and the man started to walk away.As I looked at the man leaving from Robert,I saw Robert taking out some money and went after the man to gave it to him.I asked Robert,"Why did you do that?"Robert said "He really had bad luck—what does a few dollars matter?"

    After a very long,hard day,we stopped at a Quick Trip for a soda.I got through the checkout ahead of Robert and went back out to the work truck.Beside the truck was a woman in a car.She had 3 kids and asked me if I could help—she had been evicted and had nowhere to go with her children.They were living in the car.I told her I was also hurting in these times,so I could not.Robert came out,opened the work truck and we got in.I told him about the lady.I didn't even finish the story when Robert was out his door around the truck and gave the women money to help them out.When Robert returned I asked,"Why did you do that,she didn't even ask you".He said,“I have an ex-wife（前妻）and a kid.If they need help and I am not able,someone will help them”.

    The computers changed our lives in the 1980s, the Internet changed our lives in the 1990s, and the robots will change our lives in the new century.

    Do you think there will be robots in people's homes? It's not a dream that every home will have a robot.

    Now, robots are not only able to help people do the housework, they can also help the doctors do the difficult operations, play chess with people, play the piano and so on.

    A new cooking robot is used in Beijing. It can cook all the dishes on the menu, you only need to wait two to four minutes. In the future, the robot will be a nurse, a security guard, or a partner in your life.

    Experts believe robots will be used everywhere from the industrial robots to service robots. In the future, robots will become part of the family, and provide close service for people. We all look forward to the new robot age.

    According to a recent report, about 15% of the people in the UK are members of gyms. But are they more likely to be fit?

    A study found that gym members were 14 times more active than people who didn't belong to any health club. Gym members did six hours more exercise a week, and this activity did make them fitter than non-gym members. They also spent less time sitting down every day than non-gym members. The results were the same for men and women.

    The study included 405 people between the ages of 30 and 64, and the main characteristics of those who were gym members were the same as those who were not. “But gym members did more training than non-gym members,” said the lead author, Elizabeth Schroeder of the University of Illinois.

    While it might seem clear that gym members exercise more and are healthier than non-gym members, Schroeder says this has not been directly shown before. However, the study is only designed to show a tie between gym membership and more exercise. It may be that active people like to join gyms. In the study, people who exercised as much as gym members were also in good health.

    You can get the same benefits wherever you exercise. This study shows a gym membership can make you do more exercise, but other research shows that exercising outside has other help. Outdoor activity can make you feel happy about life—especially if you run through a forest.

    Outdoor exercise is also more interesting than going to the gym. The first five minutes of outdoor exercise is especially helpful in making people feel good. But Schroeder says that a gym may also encourage greater exercise because it can be social and fun.