Recently, online hike-sharing has become the new favorite in China. In major cities, bikes in, yellow, orange, blue, white and green, can be seen almost everywhere on the street. It seems that these bikes appeared suddenly, adding a new beautiful scenery to Chinese cities.

    Both the market and the public welcome online bike-sharing, but is it really a promising business? Well, it depends. After all, online bike-sharing platforms can never get away with huge operating cost and uncertain government policy.

    Some theorists might say that online bike-sharing platforms can earn a fortune simply through deposit. Since users will always need to rent bikes, their deposit will always be kept to online bike-sharing platforms.

    However，although online bike-sharing platforms may be able to use the deposit for other purposes at the primary stage, they will have to set up a special account, so that the deposit shall be used specially for its designated (指定的) purpose. As the market gets increasingly mature, they will have to do so whether to be responsible for users or in consideration of possible government regulations.

    Now that online hike-sharing platforms can，t make profit through deposit，how can they become profitable as fiercer market unfolds? Although Hu Weiwei, CEO of Mobike, stated in an article that she would take Mobike as charitable(慈善的) project if she failed, running a startup is absolutely different from managing a charity organization. After all , she has to pay back investors' billions of investment(投资).

    To make profit, online bike-sharing platforms might have toincrease rent fee for each trip, just as Didi did

    From this aspect, it might be a really good business. If we consider full screen ads fee, recommendation fee for business owners, etc. , its annual income might reach at least RMB 15 billion. If we consider the huge operation cost, including bike repairs，bikes' service life and labor cost, there might not be much net profit left. After all, offline operation cost has always been an unbearable burden for such internet plus mode-based startups.

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    If you want to become a fluent English speaker, you should take some advice: there are four skills in learning English. They are listening, speaking, reading and writing. The most important thing you must remember is that if you want to improve your speaking and writing skills you should first master the skills of reading and listening.

    Read as much as you can. But your reading must be active. It means that you must think about the meaning of the sentences, the meaning of the unfamiliar words, etc.

    There is no need for you to pay much attention to grammar—or try to understand all the unfamiliar words you come across, but the fact you see them for the first time and recognize them whenever you see them, for example in other passages or books, is enough. It would be better to prepare yourself a notebook so you can write down the important words or sentences in it.

    As for listening, there are two choices: besides reading, you can listen every day for about 30 minutes. You can only pay attention to your reading and become skillful at your reading, then you can catch up on your listening. Since you have lots of inputs(输入) in your mind, you can easily guess what the speaker is going to say. This never means that you should not practice listening.

    For listening you can listen to cartoons or some movies that are specially made for children. Their languages are easy. Or if you are good at listening, you can listen to VOA or BBC programs every day. Again the thing to remember is being active in listening and preferably(更好地) taking some notes.

    If you follow these pieces of advice, your speaking and writing will improve automatically(自动地)，and you can be sure that with a little effort they will become perfect.

    America is a mobile society. Friendships between Americans can be close and real, yet disappear soon if situations change. Neither side feels hurt by this. Both may exchange Christmas greetings for a year or two, perhaps a few letters for a while — then no more. If the same two people meet again by chance, even years later, they pick up the friendship. This can be quite difficult for us Chinese to understand, because friendships between us flower more slowly but then may become lifelong feelings, extending (延伸) sometimes deeply into both families.

    Americans are ready to receive us foreigners at their homes, share their holidays, and their home life. They will enjoy welcoming us and be pleased if we accept their hospitality (好客) easily.

    Another difficult point for us Chinese to understand Americans is that although they include us warmly in their personal everyday lives, they don't show their politeness to us if it requires a great deal of time. This is usually the opposite of the practice in our country where we may be generous with our time. Sometimes, we, as hosts, will appear at airports even in the middle of the night to meet a friend. We may take days off to act as guides to our foreign friends. The Americans, however, express their welcome usually at homes, but truly can not manage the time to do a great deal with a visitor outside their daily routine. They will probably expect us to get ourselves from the airport to our own hotel by bus. And they expect that we will phone them from there. Once we arrive at their homes, the welcome will be full, warm and real. We will find ourselves treated hospitably.

    For the Americans, it is often considered more friendly to invite a friend to their homes than to go to restaurants, except for purely business matters. So accept their hospitality at home!

    There is some unwelcome news for students preparing for exams and officers putting in long hours—you don't need that "refreshment（提神） break" as much as you may think.

    Scientists believed it was not easy for people to continue their work if they felt the need to have a snack or a rest to make them feel better. They argued that the only way to regain willpower is by supplying more energy to our bodies with rest, food or entertainment.

    But psychologists have challenged this theory, saying weak willpower is in your head. They found that a person's mindset(理念) and belief about willpower determine how long and how well they'll be able to work on a tough mental exercise. "If you think of willpower as something that's limited, you're more likely to be tired when you perform a difficult task," said Professor Veronika Job. "But if you think of willpower as something that is not easily depleted, you can go on and on."

    The researchers led by Mr. Job designed an experiment to test the students' beliefs about willpower. After a tiring task those who believed or were led to believe that willpower was a limited resource performed worse on standard concentration tests than those who thought of willpower as something they had more control over.

    Mr. Job said, "Students who may already have trouble studying are being told that their powers of concentration are limited, and they need to take frequent breaks. But a belief in willpower as a non-limited resource makes people stronger in their ability to work through challenges."

    The findings could help people who are battling with temptation(诱惑): people following strict diets and doing exercise regularly to lose weight, people trying to overcome addictions, employees facing a tight deadline. Willpower isn't driven by a biologically based process as much as we used to think.

    A new study suggests that patients with breast cancer who take additional vitamins during chemotherapy(化疗) treatment may face increased risks.

    Researchers said the use of dietary supplements(补充剂) that increase levels of antioxidants, iron, vitamin B12 and omega-3 fatty acids appeared to lower the effectiveness of chemotherapy. Researchers reported their findings in the Journal of Clinical Oncology.

    Christine Ambrosone is the head of cancer prevention and control at the Roswell Park Comprehensive Cancer Center in Buffalo, New York. She said, "From this study and others in the literature, it seems that it may not be wise to take supplements during chemotherapy."

    "It's thought that antioxidants might interfere with the ability of chemotherapy to kill cancer cells," Ambrosone said.

    Some doctors have been advising patients for a number of years not to take antioxidants during chemotherapy. "But there was no strong empirical data for that recommendation," Ambrosone said.

    So, Ambrosone and other researchers decided to study whether supplement use might affect chemotherapy's effectiveness. They looked for evidence in an earlier study on diet, exercise, lifestyle and cancer results.

    In the earlier research, people who took part were asked about their use of supplements at the beginning of and during treatment, and about their lifestyle, diet and exercise. The researchers studied 1,134 patients who filled out the surveys and followed them for a median of six years.

    The researchers searched for possibilities that might increase the risk of the disease reappearing or of death. They found that patients who took any supplements at the beginning of and during chemotherapy were 41 percent more likely to have their breast cancer return than those who did not. In addition, the supplement takers were 40 percent more likely to die later on compared to patients using no supplements. The supplements included vitamin A, C and E. Those taking vitamin B12 and iron supplements were at greater risk of cancer returning, the researchers said.