Tulips(郁金香) are the national flower of Iran and Turkey. The European name for the flower is a misuse of the Persian word for turban(头巾), a mistake probably arising in the common Turkish custom of wearing flowers in the folds of the turban. Alternatively, the misuse may have arisen because this eastern flower, when not yet in full bloom, looks like a turban. In Persia, to give a red tulip was to declare your love for someone. The black center of the red tulip was said to represent the lover's heart, burned to a coal by love's passion.

    Originally growing in the Ottoman Empire (present-day Turkey), tulips were imported into Holland in the sixteenth century. When Carolus Clusius wrote the first major book on tulips in 1592, they became so popular that the tulips in his garden were stolen from time to time. As the Dutch Golden Age grew, so did this colorful flower. They were commonly seen in paintings and at festivals. In the mid-seventeenth century, tulips even created the first economics bubble（泡沫经济）, known as "Tulip Mania". At that time, tulips were so expensive that they were used as money until the market for them crashed.

    Today, Holland is still known for its tulips and other flowers, often sincerely called "the flower shop of the world." Tulips are planted in great fields of beautiful color, and transform the landscape into a sea of different colors. Tulip festivals are held throughout the country in spring. However, the most well-known tulip festival is organized in the Noordoostpolder, a province in the central Netherlands, each year. Held in the middle of the tulip fields, this flower festival runs from late April to early May. The Dutch people took their love of tulips abroad when they settled, and tulips and tulip festivals are now found in New York and Michigan, where the connection to their Dutch roots is still very strong.

    No one is sure how the ancient Egyptians built the pyramids near Cairo. But a new study suggests they used a little rock‘n'roll. Long-ago builders could have attached wooden pole s to the stones and rolled then across the sand, the scientists say.

     “Technically, I think what they're proposing is possible,” physicist Daniel Bonn said.

    People have long puzzled over how the Egyptians moved such huge rocks. And there's no obvious answer. On average, each of the two million big stones weighed about as much as a large pickup truck. The Egyptians somehow moved the stone blocks to the pyramid site from about one kilometer away.

    The most popular view is that Egyptian workers slid the blocks along smooth paths. Many scientists suspect workers first would have put the blocks on sleds(滑板). Then they would have dragged them along paths. To make the work easier, workers may have lubricated the paths either with wet clay or with the fat from cattle. Bonn has now tested this idea by building small sleds and dragging heavy objects over sand.

    Evidence from the sand supports this idea. Researchers found small amounts of fat, as well as a large amount of stone and the remains of paths.

    However, physicist Joseph West thinks there might have been a simpler way , who led the new study . West said , “I was inspired while watching a television program showing how sleds might have helped with pyramid construction . I thought , ‘Why don't they just try rolling the things?'“A square could be turned into a rough sort of wheel by attaching wooden poles to its sides , he realized . That , he notes , should make a block of stone” a lot easier to roll than a square”.

    So he tried it.

    He and his students tied some poles to each of four sides of a 30-kilogram stone block. That action turned the block into somewhat a wheel. Then they placed the block on the ground.

    They wrapped one end of a rope around the block and pulled. The researchers found they could easily roll the block along different kinds of paths. They calculated that rolling the block required about as much force as moving it along a slippery(滑的)path.

    West hasn't tested his idea on larger blocks, but he thinks rolling has clear advantages over sliding. At least, workers wouldn't have needed to carry cattle fat or water to smooth the paths.

    Long bus rides are like television shows.They have a beginning，a middle，and an end with commercials(广告) thrown in every three or four minutes.The commercials are unavoidable.They happen whether you want them or not.Every couple of minutes a billboard glides by outside the bus window.“Buy Super Clean Toothpaste.” “Drink Good Wet Root Beer.” “Fill up with Pacific Gas.” Only if you sleep，which is equal to turning the television set off，are you spared the unending cry of “You Need It！Buy It Now！”

    The beginning of the ride is comfortable and somewhat exciting，even if you've traveled that way before.Usually some things have changed—new houses，new buildings，sometimes even a new road.The bus driver has a style of driving and it's fun to try to figure it out the first hour or so.If the driver is particularly reckless (鲁莽的) or daring，the ride can be as thrilling as a suspense story.Will the driver pass the truck in time？Will the driver move into the right or the left hand lane？After a while，of course，the excitement dies down.Sleeping for a while helps pass the middle hours of the ride.Food always makes bus rides more interesting.But you've got to be careful of what kind of food you eat.Too much salty food can make you very thirsty between stops.

    The end of the ride is somewhat like the beginning.You know it will soon be over and there's a kind of expectation and excitement in that.The seat，of course，has become harder as the hours have passed.By now you've sat with your legs crossed，with your hands in your lap，with your hands on the armrest or even with your hands crossed behind your head.The end comes just at the right time.There are just no more ways to sit.

    2017 was an influential year for artificial intelligence (人工智能), not just in terms of the advancement of the technology itself, but also for the development of our understanding of AI's impact on our society.

    When we talk about AI, often we focus on the belief that it is going to take away certain types of jobs. However, we often ignore the fact that this technology will also slowly spread into most of our lives.

    Thanks to the development of AI, we are on the highway of IA, (human) intelligence augmentation (增强). Despite the great steps we've made in AI development and will continue to make in 2018, we are still years away from AI fully replacing human jobs. However, we are much closer to seeing the impact of AI spread into almost every job and the growth in human intelligence.

    Take a doctor for example: AI will soon be able to detect and diagnose common diseases more quickly and accurately than humans. Now, doctors can spend more of their time explaining the possible diagnoses, communicating with patients and developing unique, reliable treatment plans that are most effective for each specific patient.

    However, AI is so powerful and its adoption will only accelerate as it begins to help our work and allow us to focus on the parts of our job that are most important. But part of why AI is so attractive is also why it's so dangerous. That is, that same power allows AI that are making incorrect decisions to do so with greater speed and impact than humans have ever had.

    This is why, as AI becomes more useful in 2018, it will also become more closely examined. 2018 will be the year when companies purchasing AI products don't just ask about the power of AI—they will make sure that it is tested carefully in advance, minimizing their potential unexpected impact.

    In recent decades, social isolation has been recognized as a major risk to our health and long life. It's twice as bad for you as being overweight and nearly as bad as smoking. The rising number of people who say they are affected, across a wide range of ages, is shocking. In reality, you can suffer the ill effects of loneliness even if you are not socially isolated.

Comedian Robin Williams made a striking observation in 2014: "I used to think the worst thing in life was to end up all alone. It's not. The worst thing in life is to end up with people who make you feel all alone." Tracking large groups over time indicates that perceived（感知的）social isolation carries its own risk for morbidity（发病率）and mortality.

    The perception of isolation—from others of being in the social aspect-is not only a cause of unhappiness, it also signals danger. Fish have evolved to swim to the middle of their group when predators（捕食者）approach, mice housed in social isolation show sleep disruptions and reduced slow-wave sleep and prairie voles（田鼠）isolated from their partners then placed in an open field explore their surroundings less and concentrate on avoiding predators.

    These behaviours reflect an increased emphasis on self-preservation in the social aspect. For instance, fish on the edge of a school are more likely to be attacked by predators because they are easier to isolate and prey upon. Such observations reflect a more general principle that perceived social isolation in social animals activates neural（神经系统的）, neuroendocrine（神经内分泌的）and behavioural responses that promote short-term self-preservation. However, these responses bring a cost for long-term health and well-being.

    The range of harmful neural and behavioural effects of perceived isolation documented in adults include increased anxiety, hostility and social withdrawal; fragmented sleep and daytime tiredness; increased vascular resistance and changed gene expression and immunity; decreased impulse control; increased negativity and depressive symptoms; and increased age-related cognitive decline.

    Sadly, to date, attempts to reduce loneliness have met with limited success. A series of randomized controlled trials showed that they had only a small effect. Among the four types of interventions（介入）examined, talking therapy that focused on inappropriate thought processes had the largest impact. Social skills training, social support and increased opportunities for social contact were much less effective.

    There are a growing number of pet owners who feed their pets on raw foods, which means "uncooked" meat and bones. William Burk, a pet food specialist from the Food and Drug Administration(FDA), believes that feeding raw meat to pets is against its goal of protecting the public from health dangers, and that raw meat and bones do not have all the required nutrition that a pet needs every day.

    Recognizing how popular these foods are, the FDA has provided guidelines for producers of pet foods which contain uncooked meat for dogs, cats and other pets. The guidelines give rules to protect pet owners and pets from dangers about food safety and lack of nutrition.

    Pet owners who feed raw meat and bones to their pets should deal with these products very carefully to protect themselves against possible dangers, says Burk. Just as when you are preparing foods for human beings, use hot water and soap to wash your hands, containers, and surfaces that come into contact with the food. Don't put your hands near your mouth until you have washed them, and don't allow your pet to touch your face right after it has eaten raw meat.

    "If pet owners choose to feed bones to their pets, they should watch their pets carefully when they are eating bones," Burk says, "If a pet eats a big piece of bone that won't pass through its digestive system(消化系统), it is likely to kill the pet."