People around the world are superstitious about numbers; even those ancient Greeks believed that all numbers and their multiples had some mystical significance.

    Those numbers between 1 and 13 were in particular to have a powerful influence over the affairs of men.

    For example, it is commonly said that luck, good or bad, comes in threes; if an accident happens, two more of the same kind may be expected soon afterwards. The arrival of a letter will be followed by two others within a certain period.

    Another belief involving the number three has it that it is unlucky to light three cigarettes from the one match. If this happens, the bad luck that goes with the deed falls upon the person whose cigarette was the last to be lit. The ill-men linked to the lighting of three things from one match or candle goes back to at least the 17th century and probably earlier. It was believed that three candles alight at the same time would be sure to bring bad luck; one, two, or four, were permissible, but never just three.

    Seven was another significant number, usually regarded as a bringer of good luck. The ancient astrologers believed that the universe was governed by seven planets; students of Shakespeare will recall that the life of man was divided into seven ages. Seven horseshoes nailed to a house will protect it from all evil.

    Nine is usually thought of as a lucky number because it is the product of three times three. It was much used by the Anglo Saxons in their charms for healing.

    Another belief was that great changes occurred every 7th and 9th of a man's life. Consequently, the age of 63 (the product of nine and seven) was thought to be a very perilous time for him. If he survived his 63rd year he might hope to live to a ripe old age.

    Thirteen, as we well know, is regarded with great awe and fear. The common belief is that this derives from the fact that there were 13 people at Christ's Last Supper. This being the eve of his betrayal, it is not difficult to understand the significance given to the number by the early Christians.

    In more modern times 13 is an especially unlucky number of a dinner party, for example. Hotels will avoid numbering a floor the 13th; the progression is from 12 to 14, and no room is given the number 13. Many home owners will use 12 1/2 instead of 13 as their house number.

    Yet oddly enough, to be born on the 13th of the month is not regarded with any fear at all, which just shows how irrational we are in our superstitious beliefs.

    There is an English saying: “{#blank#}1{#/blank#} Until recently, few people took the saying seriously. Now, however, doctors have begun to look into laughter and the effects it has on the human body{#blank#}2{#/blank#}

    Tests were carried out to study the effects of laughter on the body. People watched funny films while doctors checked their hearts, blood pressure, breathing and muscles. It was found that laughter has similar effects to physical exercise{#blank#}3{#/blank#}If laughter exercises the body, it must be beneficial.

    Other tests have shown that laughter appears to be able to reduce the effect of pain on the body. In one experiment doctors produced pain in groups of students who listened to different radio programs. The group that tolerated the pain for the longest time was the group which listened to a funny program.{#blank#}4{#/blank#}

    {#blank#}5{#/blank#}They have found that even if their patients do not really feel like laughing, making them smile is enough to produce beneficial effects similar to those caused by laughter.

A. Laughter can change one's life.

B. As a result of these discoveries, some doctors in the United States now hold laughter clinics in which they help to improve their patients' condition by encouraging them to laugh.

C. The reason why laughter can reduce pain seems to be that it helps to produce a kind of chemicals in the brain which diminish both stress and pain.

D. It increases blood pressure, the heart beating and breathing; it also works several groups of muscles in the face, the stomach and even the feet.

E. Although laughter helps cure the disease, doctors still can not put this theory into clinic practice.

F. Laughter is the best medicine.

G. They have found that laughter really can improve people's health.

    What do you use to unlock your cellphone? A password? A fingerprint? Or simply a glance?

    On September 12, 2017, Apple introduced its iPhone X, which has an eye-catching feature—Face ID.

    With Face ID, Apple says, you can unlock your new iPhone by just looking at it. It is powered by a so-called TrueDepth camera system built into the front of the iPhone X.

    When the camera system sees a person's face, it uses 30,000 unseen dots to “map” the shape and outline of the face. A mathematical model of the face will then be created and stored in the phone.

    The next time the person looks at the iPhone X, the same dots are mapped onto his or her face and compared to the stored model. If the two match, then the phone unlocks. This happens in less than a second.

    Apple says the system is smart. If you change your hairstyle, put on sunglasses or makeup, or use the phone in the dark, Face ID still works.

    Although the technology sounds fancy, there are still concerns. For example, will Face ID work for twins?

    According to Apple, the chance of others to unlock your iPhone X using Face ID is one in a million. Face ID can tell the difference between twins, but the error rating（出错率）rises. So one would need to set a password then.

    Apple also emphasizes that Face ID only unlocks when you stare at it. It is what Apple calls “attention aware”. So the phone won't unlock if you are just glancing at the phone for the time. It won't work either if someone puts the phone at your sleeping face or your photo.

    Norman Borlaug, who is making a difference, is known around the world. He is often described as the man who has saved more lives than any other person in history. Norman Borlaug is considered the father of what has been called the Green Revolution. His ideas about agriculture increased crop production and ended hunger in many nations. Mr. Borlaug continues to be a leader among agricultural researchers.

    Norman Borlaug was born in 1914 on a farm in the American state of Iowa. In the middle of the 20th century, world population was expanding faster than food production. Experts said many people in developing countries would face starvation.

    Norman Borlaug was an agricultural researcher at the International Maize and Wheat Improvement Center in Mexico. He developed methods of growing wheat that increased the amount harvested by three times. He later repeated this success in India, Pakistan and Africa.

    His methods of farming saved millions of people who would have starved to death. Norman Borlaug was given the Nobel Peace Prize for his efforts in 1970.

    Norman Borlaug is still urging experts to think about the needs of people around the world. His latest concern is a disease in wheat called UG99. He says it has the power to destroy most of the wheat being grown around the world. He says reductions in agricultural programs have made it harder to take action against such threats.

    Mr. Borlaug's granddaughter Julie works at the center named after him at Texas A&M University in Dallas. She says his worry about food problems rises from the belief that hunger is unacceptable. She says Norman Borlaug still believes it is our responsibility as human beings to feed one another.

    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.

    Growing up, I wanted to be just like my mom. She was kind. People always seemed to feel comfortable in her presence. For years, she was a volunteer in our community. I loved going to the local nursing home with her where she taught a ceramics(制陶技术) class.

    On one summer day, Mama told me to get changed and meet her at the car.

I had planned to spend the day at the lake with friends. Why did she have to ruin everything? I imagined the cool lake water. Irritated，I climbed into the car and slammed the door shut. We sat in silence. I was too upset to make conversation.

    "Tasha, would you like to know where we are going?" Mama asked calmly.

    "No," I said.

    "We are going to volunteer at a children's shelter today. I have been there before and I think it would benefit you," she explained.

    When we reached the shelter, Mama rang the doorbell. Moments later, we were greeted by a woman. She led us to the front room where all of the children were playing. I noticed a baby whose body was scarred with iron marks. I was told it was because she wouldn't stop crying. The majority of the children had noticeable physical scars. Others hid their emotional wounds.

    As I took in my surroundings, I felt a gentle pull on my shirt. I looked down to see a little girl looking up at me. "Hi. You want to play dolls with me?" she asked. I looked over at Mama for reinforcement. She smiled and nodded. I turned back and said, "Sure." Her tiny hand reached up and held mine, as if to comfort me.

    My mom taught me a valuable lesson that summer. I returned to the shelter with her several times. During those visits, some of the children shared their troubled pasts with me and I learned to be grateful for what I had. Today as I try to instill (逐渐灌输) these values in my own child, I reflect back to that experience. It was a time that I will never forget.