The bed should be reserved as a place for sleep, but people tend to read an iPad a lot in bed before they go to sleep.

    Charles Czeisler, a professor at Harvard Medical School, and his colleagues got a small group of people for an experiment. For five days in a row, the people read either a paper book or an iPad for four hours before sleep. Their sleep patterns were monitored all night. Before and after each trial period, the people took hourly blood tests to paint a day-long picture of just how much melatonin (褪黑激素) was in their blood at any given time.

    When subjects read on the iPad as compared to the paper books, they reported feeling less sleepy at night and less active the following morning. People also took longer to fall asleep on the iPad nights, and the blood tests showed that their melatonin secretion (分泌) was delayed by an hour and a half.

    The researchers conclude in today's journal article that given the rise of e-readers and the increasingly widespread use of e-things among children and adolescents, more research into the long-term consequences of these devices on health and safety is urgently needed. Czeisler and colleagues go on, in the research paper, to note：“Reading an iPad in bed may increase cancer risk.”

    However, software has been developed that can reduce some of the blue light from the screens of phones and computers according to time of day, and there are also glasses that are made to filter (过滤) short wavelengths. While they seem like a logical solution for the nighttime tech users, it needs more research.

    With the start of the new term, the students around the country exchange their fun and fashionable clothes for boring school uniforms. But not all schools are fashion deserts. Colorful sports shoes, school bags, T-shirts and even drink containers are breathing life into campuses.

    "The uniform makes us look like a bunch of clones, especially when we are doing morning exercises on the playground," said Qing Pei, a Senior 2 from Shanghai Qibao High School. "But the boys wear different sports shoes and girls have different decorations in their hair. These are the areas where you can express yourself," said Qing.

    Although it might be strange for boys to talk about fashion, they do care about what they wear in school, especially shoes, according to Qing.

    "Nike and Adidas basketball shoes, although they are still the must-have items for many of my friends, are becoming out-of-date," Qing added. He explained that "Since Liu Xiang ran so fast in Athens, running shoes are becoming popular in this autumn."

    "Still in fashion are the various baseball caps and American-style T-shirts with random (随意的) English words printed on them," said Qing. "The accuracy of the written message is not important. Often, the words are misspelt. Sometimes they do not even make sense, "Qing said with a smile.

    Besides sports shoes and T-shirts, styles and colors of school bags are another opportunity for students to express their taste in fashion. Some bags are made more eye-catching by decorating them with small hanging dolls.

    Other fashionable items are the colorful drink containers which are now popular among girls this term.

    "Some teachers are surprised to see a teenager sucking a bottle like this at school and criticize it as a childish regression (退化). But some girls just love it," said Yang Rui, a Senior 3. from High School attached to Xi'an Jiaotong University.

    My husband and I recently went to Disney World with our three children. We had a wonderful time. Besides, I experienced something that left a deep impression on me.

    Our children were excited about the attraction where children could drive the cars. They were so delighted that I decided to stand beside the track to get pictures of everyone as they drove past on the track.

    As I waited for them to drive by, I noticed a car with a father and his son who was about 7 years old. They rolled down the hill at the beginning, but suddenly the car stopped. The young driver looked nervous, "I can't do it." His father quietly said, "Yes, you can."

    "No. I can't!"

    "Yes, you can, son."

    The little guy was almost in tears, "I can't!" With deep patience, the father said, "Son, you can do this. I'm going to help you." A moment later, with the father helping his son, the two went smoothly (顺利地) on their way down the track.

    The scene brought tears to my eyes and it reminded (使想起) me of my dear father. Just like that little boy's dad, my father used to say the same words to me. Every time things got hard or when I experienced setbacks along the way, he would say, "Michelle, you can do this. I'm going to help you."

    Time and time again the words greatly encouraged me on the journey. I'm aware that I can't do things under my own power, but the words "Yes, you can" come beside me and give me wisdom and strength. As I benefited (受益) a lot from them, I often tell my children never to say "I can't" easily when they meet something difficult.

    About three decades ago, China was known as the "Bicycle Kingdom".But the two­wheeled transport's popularity began to fade, with many bikes soon replaced by their fuel­powered competitors.

    But recent months have seen a renaissance of the bike across China, with an increasing number of people choosing cycling instead of driving to schools, to workplaces or to do sightseeing. The introduction of bike­sharing schemes, first developed by new companies like Ofo and Mobike, has brought the trend to a new level. According to data from iResearch Consulting Group, the first week of this year saw 5.85 million active users of Mobike while Ofo had 1.4 million active users.

    People can unlock the shared bikes by simply using their smartphones. The bikes are equipped with GPS and can be left anywhere in public places for the next user. They're popular among many Chinese people as they provide an effective answer to the "last mile" problem, which refers to a person's final journey. "In places where the subway doesn't reach and where it's difficult to change from one kind of transport to another, it's so easy to get where you want to go with Mobike," Hu Hong, 29, said. She rides a bike to work.

    However, the schemes have also led to problems such as illegal parking, vandalism (故意破坏) and theft. "Bike­sharing is a greener method of transportation and provides a user­friendly experience," said Liu Xiaoming, Vice­Minister of Transport. "But it's a combination of online and offline business. Operators are usually strong in online services, but lack offline business experience."

    In fact, these problems are also shared by bike­sharing schemes abroad. Set up in 2007, Vélib is a large­scale public bike sharing system in Paris. By October, 2009, a large number of Vélib's initial bikes had to be replaced due to vandalism or theft. Bikes were found hanging from lampposts (街灯柱) or thrown into the Seine River.

Many scientists today are convinced that life exists elsewhere in the universe—life probably much like that on our own planet. They reason in the following way.

    As far as astronomers can determine, the entire universe is built of the same matter. They have no reason to doubt that matter obeys the same laws in every part of the universe. Therefore, it is reasonable to guess that other stars, with their own planets, were born in the same way as our own solar system. What we know of life on earth suggests that life will arise wherever the proper conditions exist.

    Life requires the right amount and kind of atmosphere. This eliminates(除去) all those planets in the universe that are not about the same size and weight as the earth. A smaller planet would lose its atmosphere; a larger one would hold too much of it.

    Life also requires a steady supply of heat and light. This eliminates double stars, or stars that flare up suddenly. Only single stars that are steady sources of heat and light like our sun would qualify.

    Finally, life could evolve(进化) only if the planet is just the right distance from its sun. With a weaker sun than our own, the planet would have to be closer to it. With a stronger sun, it would have to be farther away.

    If we suppose that every star in the universe has a family of planets, then how many planets might support life? First, eliminate those stars that are not like our sun. Next eliminate most of their planets; they are either too far from or too close to their suns. Then eliminate all those planets which are not the same size and weight as the earth. Finally, remember that the proper conditions do not necessarily mean that life actually does exist on a planet. It may not have begun yet, or it may have already died out.

    This process of elimination seems to leave very few planets on which earthlike life might be found. However, even if life could exist on only one planet in a million, there are so many billions of planets that this would still leave a vast number on which life could exist.