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.

根据短文内容，选择最佳答案，并将选定答案的字母标号填在题前括号内。

    The Great Pyramid(金字塔)was built nearly 5,000 years ago for a king called Khufu. It is on the west bank of the Nile River. In fact, all the pyramids along the Nile River are on its west bank. The ancient Egyptians thought of the rising of the sun as the beginning of life and the setting of the sun as the end of life. This is why their bodies were buried on the west of the Nile.

    It is very hard to realize just how big the Great pyramid is. It has over 2,000,000 pieces of stones. Most of these big stones weigh two and a half tons each. Some even weigh fifteen tons. Without machinery, the ancient Egyptians cut and moved and lifted each of these stones. Almost all the stones came from the east bank of the Nile, and they were taken across the river in boat. It took more than 100,000 people twenty years to build the Great Pyramid.

    The Great Pyramid is over 450 feet high today. Each of the sides of the Pyramid is 755 feet long. It takes about twenty minutes to walk all the way around it.

    In 1977, a dead author of detective stories saved the life of a 19-month-old baby in a most unusual way. The author was Agatha Christie, one of the most successful writers of detective stories in the world.

    In June 1977, a baby girl became seriously ill in Qatar, near Saudi Arabia. Doctors were unable to find out the cause of her illness with confidence, so she was sent to Hammersmith Hospital in London. She was then only semi-conscious and on the "Dangerously Ill" list. A team of doctors hurried to examine the baby only to discover that they, too, were confused by the very unusual symptoms (症状). While they were discussing the baby's case, a nurse asked to speak to them.

    "Excuse me," said Nurse Marsha Maitlan, "but I think the baby is suffering from thallium (铊) poisoning(中毒)."

    "What makes you think that?" Dr. Brown asked. "Thallium poisoning is extremely rare."

    "A few days ago, I was reading a novel called A Pale Horse by Agatha Christie," Nurse Maitlan explained. "In the book, somebody uses thallium poison, and all the symptoms are described. They're exactly the same as the baby's."

    "You're very thoughtful and you may be right," another doctor said. "We'll carry out some tests and find out whether it's thallium or not."

    Tests showed that the baby had indeed been poisoned by thallium, a rare metallic substance(物质) used in making special glass. Once they knew the cause of the illness, the doctors were able to give the baby the correct treatment. She soon recovered and was sent back to Qatar. Later it was reported that the poison might have come from an insecticide (杀虫剂) used in Qatar.

A Teenage Inventor

    The world could be one step closer to quick and inexpensive Ebola detection thanks to a teenager from Connecticut.

    Olivia Hallisey, a junior at Greenwich High School, was awarded $50,000 in the Google Science Fair for her new method that detects Ebola, a virus that causes bleeding from different parts of the body and usually causes death. Olivia's method is to ask patients to put their saliva (唾液) onto a testing card. The card changes color if the person is catching Ebloa. Present Ebloa tests take up to 12 hours and cost $1,000. Olivia's method, however, can be done just in 30 minutes for about $25. Besides, the sample (样本) doesn't have to be put in a refrigerator thanks to the silk material Olivia uses to produce the testing cards.

    Olivia was inspired to deal with this global problem after watching the news that more than 10,000 people died from Ebola in West Africa. She was particularly worried about the fact that, while the acts of involvement can improve survival rates, present detection methods are costly, time-consuming and require complex tools. Olivia got help from her science research teacher. She drew out directions from past research, and figured out detection systems that have proven to work with other diseases, including Lyme disease and yellow fever.

    "What affects one country affects everyone," Olivia told CNBC. "We have to work together to find answers to the huge challenges which cause harm to the global health." The Connecticut's teen, who hopes to become a doctor one day, was named the Google Science Fair winner in the competition of 20 competitors from across the globe. The fair is open to young people between the ages of 13 and 18 in most countries.

    Olivia hopes her success will inspire other girls interested in science and computers. "I would just encourage girls to try it in the beginning, and remind them that they don't have to feel naturally drawn or feel like they have a special talent for maths or science," she told CNBC, "but just really look at something they are interested in and then think how to improve something or make it more enjoyable or relate it to their interests."

    One early morning, I went into the living room to find my mother reading a thick book called Best Loved Poems to Read Again and Again. My interest was aroused only by the fact that the word "Poems" appeared in big, hot pink letters.

    "Is it good?" I asked her. "Yeah," she answered. "There's one I really like and you'll like it, too." I leaned forward." 'Patty Poem,'" she read the title. Who is Patty? I wondered. The poem began:

    She never puts her toys away,

    Just leaves them scattered ⁽散乱的)where they lay,...

    The poem was just three short sections. The final one came quickly:

    When she grows and gathers(稳重的)poise,

    I'll miss her harum-scarum(莽撞的) noise,

    And look in vain for scattered(徒劳地)toys.

    And I'll be sad.

    A terrible sorrow washed over me. Whoever Patty was, she was a mean girl. Then, the shock.

    "It's you, honey," My mother said sadly.

    To my mother, the poem conveyed a parent's affection when her child grows up and leaves. To me, the "she" in the poem was horror. It was my mama who would be sad. It was so terrible. I burst out crying.

    "What's wrong?" my mother asked.

    "Oh Mama," I cried. "I don't want to grow up ever!"

She smiled. "Honey, it's okay. You're not growing up anytime soon. And when you do, I'll still love you, okay?"

    I calmed down. But I could not help thinking about that silly poem. After several years, I read the poem again and was confused. It all fit so well together, like a simple puzzle easy to understand, yet it was still beautiful. I was now attracted by the idea of poetry, words that had the power to make or break a person's world.

    I have since fallen in love with other poems, but "Patty Poem" remains my poem. After all, "Patty Poem" gave me my love for poetry.

    People traveling long distances frequently have to decide whether they would prefer to go by land, sea, or air. Hardly can anyone positively enjoy sitting in a train for more than a few hours. Train carriages soon get crowded. Reading is only a partial solution, for the monotonous(单调的) rhythm of the wheels clicking on the rails soon makes you sleep. During the day, sleep comes in snatches. While at night you rarely manage to sleep. Inevitably you arrive at your destination almost exhausted.

    Long car journey are even less pleasant, for it is quite impossible even to read. On motorways you can, at least, travel fairly safely at high speed, but more often than not, the greater span of the journey is spent on narrow, uneven roads which are crowded with traffic.

    By comparison, trips by sea offer a great variety of civilized comforts. You can stretch your legs on the broad decks, play games, swim, meet interesting people and enjoy good food-always assuming, of course, that the sea is calm. If it is not and you are likely to get seasick, no form of transport could be worse. Even if you travel in ideal weather, sea journeys take a long time. Relatively few people are prepared to sacrifice up to a third of their holidays for the pleasure of traveling on a ship.

    Airplanes have the reputation of being dangerous and a little expensive. But nothing can match them for speed and comfort. Traveling at a height of 30,000 feet and at over 500 miles an hour is a pleasant experience. For a few hours, you settle back in a deep armchair to enjoy the flight. The real relaxation can be a free film show and some other services. An airplane also offers you an unusual and breathtaking view of the world. You really see the shape of the land. If the landscape is hidden from the view, you can enjoy the extraordinary sight of unbroken cloud plains that stretch on for miles before you, while the sun shines brilliantly in a clear sky. The journey is so smooth that there is nothing to prevent you from reading or sleeping. However you decide to spend your time, one thing is certain: you will arrive at your destination fresh and untired.