How can you gain knowledge of the world without books or teachers? Visiting various kinds of world-famous museums may be your best choice. If you are interested ，here are 3 famous museums well worth visiting.
National Gallery, London 2017 attendance: 6,263,000

    The National Gallery originally opened in 1824 in a Pall Mall townhouse with just 38paintings. Today's collection contains over 2, 300 works from the 13th to 19th centuries, which you can appreciate free of charge. The works range in style and time period, but hey, everyone needs to see Van Gogh's Sunflowers in Room 43 at least once, for which the Museum is famous.

    Opening time: daily 10 am—6 pm Friday 10 am—9 pm

    Closed time: January and 24—26 December

    Admission: Free
National Air and Space Museum, Washington, D. C.

    2017 attendance: 7,500,000

    The National Air and Space Museum, part of the Smithsonian Institution, hosts the world's largest collection of aviation and space artifacts. You'll see crowds flocking toward the 1903Wright Flyer and Apollo 11command module, but don't forget about NASA's often—overlooked Stardust probe.

    Hours and Admission :Open every day except December 25.

    Free admission and tickets (free) are needed.

    ⒈A maximum of 4000 free tickets will be issued each day at the museum.

    ⒉Each visitor can once collect one free ticket of the day with valid ID (Passport ).

    Regular Hours :10:00 am to 5:30 pm

    Extended Hours :10:00 am to 7:30pm Fridays, Saturdays and Sundays

National Museum of China, Beijing

    2017 attendance: 7,550,000

    Founded in February 2003, this huge, well-curated museum sits on the edge of Beijing's Tiananmen Square and is free to enter. It houses more than 1.3 million exhibition pieces in its 40halls ，focused primarily on China's achievements in history, culture, and art.

    Opening Hours :9 :00—17:00

    (No Entry after 16:00) Closed on Mondays

    Museum Visiting Tips: Limit the number of bags( only one handbag is allowed ). All visitors are screened through metal detector upon entry. The fewer items you bring inside the Museum. Before you visit, please review the list of prohibited items, Visitors carrying prohibited items will not be allowed inside the Museum, s0 please leave them at home or in your car.

    No Food or Drink: Only bottled water is permitted in the Museum

    Bedtime on the Orient Express. We stood in the corridor while a woman pulled our bunk beds (双层铺) into place-- there wasn't room in the carriage for all three of us. Barking the news that she would be waking us at 7 a.m. with a cup of instant coffee and a piece of cheese, the woman left and we retired for the night.

    'Bunk beds?' you may be thinking. Small carriage? Instant coffee? This can't be the real Orient Express! Oh, but it is. This is a very real Orient Express indeed. In search of a long weekend in Vienna, there seemed no more attractive way for my friend and me to get there.

    The original Orient Express service was started in 1863. Luxury carriages ran the route from Paris, France to Giugiu, Romania. In 1934, Agatha Christie sent Hercule Poirot on just such a journey in her novel Murder on the Orient Express. However, there was a rise in air travel which was quicker and cheaper and eventually the whole operation was brought to a halt in 1977. The name was reused in 1982, when the Venice Simplon-Orient-Expresss took its first voyage between London and Venice.

    Admittedly I would have loved to take the Venice Simplon-Orient-Express, with its on-board shop and piano in the bar, but at around £1,700 per person for a four-night one-way journey, it was too expensive for us. So we chose this excellent way of buying into the romance for a small amount of the cost.

    But we loved it. Ours was no luxury bedroom, but it had its own rough charm-- not to mention the magic of travelling across international borders overnight. I haven't slept in a bunk bed since I was seven, and climbing up into it took 25 years off me. For one night only, it was comfortably appealing. Naturally, I took a copy of Murder on the Orient Express to read on the train. I smiled at the descriptions of airy dining cars and fresh coffee.

    My weekend in Vienna was wonderful and reunited with the cut-price Orient Express at the end of the holiday, we were rather delighted to see our little carriage again. Good old bunk beds. Terrifying old attendant. And best of all, nobody got murdered.

    When Boris left school, he could not find a job. He tried hard and he wrote letters to many companies until he could not afford to buy any more stamps. Boris began to lose his confidence, then depressed. Still he went on trying and still he failed. He began to think that he had no future at all.

    "Why don't you start your own business?" one of his uncles told him. "The world is a money­locker. You'd better find a way of opening it."

    "But what can I do?"

    "Get out and have a look round." advised his uncle. "See what people want; then give it to them, and they will pay for it."

    Boris began to cycle around the town and found a suitable piece of waste ground in the end. Then he set up his business as a cycle repairer. He worked hard, made friends with his customers and gradually managed to win his good fame. A few months later, he found that he had more work than he could deal with by himself. He found a number of empty shops but they were all no good: in the wrong position, too expensive or with some other problems. But at long last, he managed to find an empty shop in a new place where there were plenty of customers but no competition.

    Boris and his assistant taught themselves how to repair motor­cycles. Slowly but surely the profits increased and the business developed. At last, Boris had managed to open the money­locker and found bank notes and gold coins inside.

When adult humans meet a baby, many can't help speaking in a higher-pitched (更高音的) and sing-song y voice. This shift, known as parentese, is not unique to humans. It has also been observed in animals like monkeys and gorillas. Now, scientists are adding one more species to that list: bottle-nose dolphins.

Dolphins are intelligent animals that live and hunt in groups. They communicate in a unique way: Every individual produces its own signature sound that acts much like an ID card, usually by its first birthday. But how does each come up with its distinctive whistle? For babies, it might have something to do with listening to Mum. To solve this mystery, researchers examined the sounds mother dolphins make.

Scientists studied 34 years' worth of recordings of sounds made by 19 female bottle-nose dolphins. When the mother dolphins were near their young, they continued to make their signature sounds, but at a higher frequency. They also used a wider range of frequencies than they did when their babies were not nearby.

This discovery suggests that using these modifications, mother dolphins assist their young in learning how to produce these calls themselves. Since baby dolphins often spend some years with their mothers before living on their own, it makes sense that this adaptation would help them learn to communicate. At the very least, the higher-pitched whistle likely gets the babies' attention. "It's important for a baby to know, ‘Oh, Mum's talking to me now,'" says marine biologist Janet Mann.

This kind of research could help us understand how language developed in humans. "It is absolutely essential to have basic knowledge about other species and how they communicate," says Mann. "I would be really interested to see whether dolphins also change their sounds when interacting with babies of others, which is what happens in humans."

I was at the grocery shop1 last-minute items for Easter dinner when I 2 from the corner of my eye the most wonderful flower I had ever seen. It was, as I later learned, a peony (牡丹).

I was so3 that I was going to buy myself flowers. I'd4 done this before. On the way home, I wondered why I had never really been5 to any flowers before.6 , I'd been on this earth for over half a century.

7 in England, my immigrant (移民) family viewed flowers as 8 since survival was our priority. Dad worked on the railways, and Mom, before her 9 , worked in a factory. Our small garden was filled with vegetables10 flowers, as Mom and Dad often said, "These will keep us alive if we can't get them from the 11 ."

We also built an underground oven (烤炉), where Mom and Dad would make flatbread (薄面饼). The smell of this flatbread12 us and anchored (使扎根) us to our lives in England. When Mother's Day came, Mom would say, "Why waste money on flowers? They'll just die. Buy shoes or coats instead." So, we kids made food for her at home. My mother 13 years ago after a long illness. If she were still alive today, she' d probably 14 her head at me for buying flowers.15 , I still wish I'd had the chance to show her this beautiful flower and buy it for her on Mother's Day