Arriving in Sydney on his own from India, my husband, Rashid, stayed in a hotel for a short time while looking for a house for me and our children.

    During the first week of his stay, he went out one day to do some shopping. He came back in the late afternoon to discover that his suitcase was gone. He was extremely worried as the suitcase had all his important papers, including his passport.

    He reported the case to the police and then sat there, lost and lonely in the strange city, thinking of the terrible troubles of getting all the paperwork organized again from a faraway country while trying to settle down in a new one.

    Late in the evening, the phone rang. It was a stranger. He was trying to pronounce my husband's name and was asking him a lot of questions. Then he said they had found a pile(堆) of papers in their trash can(垃圾桶) that had been left out on the footpath.

    My husband rushed to their home to find a kind family holding all his papers and documents(文件). Their young daughter had gone to the trash can and found a pile of unfamiliar(不熟悉的) papers. Her parents had carefully sorted them out, although they had found mainly foreign addresses on most of the documents. At last they had seen a half-written letter in the pile in which my husband had given his new telephone number to a friend.

    That family not only restored the important documents to us that day but also restored our faith and trust in people. We still remember their kindness and often send a warm wish their way.

    The National Air and Space Museum in Washington，DC has thousands of objects on display，including the 1903 Wright Flyer，Charles Lindbergh's Spirit of St．Louis，the Apollo 11 Command Module Columbia，and a lunar rock you can touch．In addition to our exhibition galleries，you may want to visit the Albert Einstein Planetarium，Lockheed Martin IMAX Theater，and the Public Observatory on the east end．There are many things to do at the Museum in DC．We offer daily tours and educational activities for both children and adults．We also have scheduled lectures and events throughout the year．

Hours & Admission：Open every day except December 25．Admission is free．

    Regular hours：10：00 am to 5：30 pm

    Extended Hours：10：00 am to 7：30 pm

    December 26-30，2016

    March 30-April 20，2017

    Fridays and Saturdays，April 24-May 16，2017

    May 17-September 7，2017

    VISITING TIPS：

    Limit the Number of Bags：All visitors are screened through metal detectors upon entry．The fewer items you bring inside the Museum，the faster your entry．Before you visit，please review the list of prohibited items，which include pocket knives and tripods（三脚架）．Visitors carrying prohibited items will not be allowed inside the museum，so please leave them at home or in your car．

    No food and Drink：Only bottled water is permitted in the Museum．You may only consume food and other drinks in the Food Court，not in the Museum．Groups who bring food are encouraged to picnic on the National Mall．

Please Take Photos：You are welcome to take photos for personal use．However，tripods and monopods（单脚架） are not permitted without approval．

    First Aid：The Museum has a First Aid office and a nurse on duty．Please contact the nearest security officer or the Welcome Center for assistance．

    Visit the Welcome Center：At our Welcome Center in the South Lobby，staff and volunteers can answer any questions you have during your visit．

    Phone：202-633-2214

    E-mail：NASM-VisitorServices@si．edu

    While Jennifer was at home taking an online exam for her business law class, a monitor a few hundred miles away was watching her every move.

    Using a web camera equipped in Jennifer's Los Angeles apartment, the monitor in Phoenix tracked how frequently her eyes moved from the computer screen and listened for the secret sounds of a possible helper in the room. Her Internet access was locked－remotely－to prevent Internet searches, and her typing style was analyzed to make sure she was who she said she was: Did she enter her student number at the same speed as she had in the past? Or was she slowing down?

    In the battle against cheating，this is the cutting_edge and a key to encourage honesty in the booming field of online education. The technology gives trust to the entire system，to the institution and to online education in general. Only with solid measures against cheating, experts say, can Internet universities show that their exams and diplomas are valid—that students haven't just searched the Internet to get the right answers.

    Although online classes have existed for more than a decade, the concern over cheating has become sharper in the last year with the growth of “open online courses.” Private colleges, public universities and corporations are jumping into the online education field. Spending millions of dollars to attract potential students, while also taking steps to help guarantee honesty at a distance.

    Aside from the web cameras, a number of other high-tech methods are becoming increasingly popular. Among them are programs that check students' identities using personal information, such as the telephone numbers they once used.

    Other programs can produce unique exams by drawing on a large list of questions and can recognize possible cheaters by analyzing whether difficult test questions are answered at the same speed as easy ones. As in many university classes, term papers are scanned against some large Internet data banks for cheating.

    Four teenage girls from Minnesota, US. 120 hours of non-stop togetherness. No cellphones. This is not a reality show, but an adventure journey.

    "It was really perfect," said Julia Ruelle of her recent adventure to the Boundary Waters Canoe Area Wilderness with three of her childhood friends. "By unplugging, we had an amazing time."

    Last year, the 16-year-old took part in an essay contest and carried off a prize. The award was a 5-day canoe and camping adventure with up to three friends. No parents or guides would be there. So Julia invited her friends Anna Wander, Madeline Wilson and Julianna Torelli.

    The four Minnetonka High School juniors arrived in Ely for training the day before they began the journey. They set out the next day at 7 a.m., quickly developing a routine.

    "We were done paddling by noon," Julia said. "We ate lunch at the campsites and then it was time for hammocks (吊床), reading, making friendship bracelets (手镯) and talking."

    The girls had all had experience in the outdoors before.

    Anna had been to the Boundary Waters with her family. "I love how you are separated from everything in your life, especially technology," Anna said. Without her phone, she said, "I'm less worried about things." Madeline, too, had been to the Boundary Waters a few years back. "But this time, I had to paddle right and set up camp," she said. The girls made fire and cooked meal together. No one was ever hungry or homesick, but they were nervous the final night as they waited out a thunderstorm. They left wet sleeping bags in one tent, and squeezed into another for the night. "Every thunderstorm in the Boundary Waters feels huge," Julia said.

    On the car ride home, they were all on their phones catching up with friends. "It was a little at a loss turning my phone on," said Anna. "Mental health can be improved so much in the Boundary Waters. It really helps to get away and reconnect with yourself."

Inventor, physicist, surveyor, astronomer, biologist, artist... Robert Hooke was all these and more. Some say he was the greatest experimental scientist of the 17th century. In the course of his work, he cooperated with famous men of science like Isaac Newton, and the great architect, Christopher Wren.

Hooke's early education began at home, under the guidance of his father. He entered Westminster School at the age of 13, and from there went to Oxford, where he came in contact with some of the best scientists in England. Hooke impressed them with his skills at designing experiments and inventing instruments. In 1662, at the age of 28, he was named Curator of Experiments at the newly formed Royal Society of London — meaning that he was responsible for demonstrating new experiments at the society's weekly meeting. Hooke accepted the job, even though he knew that the society had no money to pay him!

Watching living things through a microscope was one of his favourite pastimes. He invented a compound microscope for this purpose. One day while observing a cork under a microscope, he saw honeycomb­like structures. There were cells — the smallest units of life. In fact, it was Hooke who invented the term "cell" as the box­like cells of the cork reminded him of the cells of a monastery．

Another achievement of Hooke's was his book Micrographia, which introduced the enormous potential of the microscope. It contains fascinating drawings of the thing he saw under the microscope. The book also includes, among other things, ideas on gravity, light and burning that may have helped scientists like Newton when they were developing their own theories on these phenomena.

Hooke made a valuable contribution to astronomy too. A crater on the moon is named after him in honour of his services to this branch of science.

Teenagers who spend more than six hours online on school days are more likely to be lonely and skip school,according to an international study.

The study examined the home Internet use,well-being(幸福) and behaviour of 296,000 15-year-olds in 41 countries.More than one in four spent more than four hours per day online outside of school.The study found lower levels of well-being among students who spent more than six hours per day online.They were twice as likely as teenagers spending one and two hours per day online to report that they felt lonely at school.These extreme Internet users were also especially at risk of "behaving in problematic ways at school,such as arriving late or skipping class".

The report said,"Lower levels of engagement(密切关系) with school may be connected to less sense of belonging at school.It is also possible that skipping class and arriving late for school are the consequence of lack of sleep among extreme Internet users."It adds,"Parents,schools and health professionals can work together to watch and plan children's use of new media."

The study also found that countries that invest(投资) heavily in Information and Communication Technology(ICT) in schools have seen no considerable difference in 15-year-olds' achievement in reading,maths or science tests.The study results suggest limited use of computers at school may be better than not using them at all.However,students who use computers very frequently at school do a lot worse in most learning outcomes.The report says,"In the end,technology can strengthen great teaching,but great technology cannot replace poor teaching."