Sometimes, you just can't help it. Maybe you're watching a sad movie, or thinking about the friend who moved away. Next thing you know, your eyes are watering, and you havetears running down your cheeks. Why do peoplecry when they are emotional? What are tears? Scientists are working hard to find the answers to these questions.

    Ad Vingerhoets is a professor of psychology at Tilburg University, in the Netherlands. He is one ofthe few scientists in the world who have studied crying. According to Vingerhoets, there are three types of tears. Basal tearsare the first type. Theylubricate(润滑) the eyes andact as a protective barrier between the eye and the rest of the World. Next arereflex tears. They wash youreyes clean when something gets in them. Finally, there are emotional tears. “These are released in response to emotional states, ”explains Vingerhoets. “Especially when we feel helpless.”

    Scientists believe that crying has something to do with how humans developed and learned to depend on each other.“Humans are very complex social creatures,”says Lauren Bylsma, a professor at the University of Pittsburgh, in Pennsylvania.“It seems that tears serve to arouse help and support from others," She says. “Another reason we weep is that humans have the longest developmental period of almost any animal. It takes along time to grow up. ”

    Vingerhoets agrees. “I think that the reason why humans shed tears(流眼泪) has somethingto do with our childhood,”he says. “That's the time when we are stir dependent on adults for love and protection and care. The major advantage of emotional tears is that you can target them at a specific person.”Vingerhoets says this ability to target someone could have come in hand in prehistorictimes, when humans were living among dangerous animals. Crying couldattract predators(捕食者). Tears were asafer way to get attention. In this case, it is better to use a silent signal to ask for help,”he says.

    Vingerhoets and Bylsma do frequent studies to better understand why humans cry. According to Byhma, there is still much more to discover. “It's surprising,”she says,“how much we still don't know.”

    Most people who move to a foreign country may experience a period of time when they have a lot of stress in the new culture. This feeling is often called “culture shock” and it is important to learn how to deal with culture shock. First of all, you should know that everyone in a new situation will go through some form of culture shock. There are four general stages of cultural adjustment(适应).

    The first stage is usually referred to as the honeymoon stage. Upon arriving in a new environment, you'll be interested in the new culture. Everything will seem exciting, and everyone will seem friendly and helpful.

    The second stage is called the withdrawal stage. The excitement that you felt before changes to frustration(沮丧) as you find it difficult to deal with new problems. The language is hard to learn; friends are hard to make; simple things like shopping and going to the bank are challenges. It is at this stage that you are likely to feel anxious and homesick.

If you are one of those who manage to stick it out (坚持下来), you will enter the third stage—- the recovery stage. At this point, you'll feel more confident in the new culture. You'll start to understand and accept the way things are done and the way people behave in your new environment.

The last stage is the stability stage—- this is the point when people start to feel at home in the new culture. At this stage, you will behave well in the new culture, and prefer some aspects(方面) of the new culture to your own culture.

    There is, in a sense, a fifth stage to this process. If you decide to return home after a long period in a new culture, you may experience what is called “reverse culture shock”. This means that you may find aspects of your own culture “foreign”, because you're so used to the new culture. Reverse culture shock is usually pretty mild(温和的) and doesn't last for very long.

    Even now, almost a year after their astonishing act of group heroism, the dozens of people who risked their lives to save two boys from drowning in Panama City Beach, are still remembered.

    The story began on July 8, 2017. Members of the Ursrey family, eight in total, were enjoying an evening together at the beach. As the sun sank lower on the horizon（地平线）, the two boys—Noah, 11, and Stephen, 8—took their skateboards and walked into the waves without the grown-ups noticing. When the boys were about 70 yards from shore, they realized that the ocean pulled them out to sea. After trying and failing to paddle（涉水）back, they started waving and screaming for help. But the lifeguards had clocked out for the evening.

    The boys had been struggling for several minutes when Brittany and Tabatha Monroe, a married couple from Georgia, wandered by. They didn't see the boys at first, but they heard them.

    They jumped into the water and easily reached the brothers, who were still in fairly shallow water. The woman reassured the frightened boys and seized their skateboards, telling them they would be safe and then discovered that they, too, were now in a world of trouble. They couldn't get back to shore and could barely and only occasionally hit the sandy bottom with their feet. After a few minutes, it was clear to the woman that they were all trapped in a terrible whirlpool.

    Then scores of tourists were walking to them, hand in hand, forming a line. Soon the first person held the woman's hand. In turn, her husband and the two boys joined her. The long line moved slowly until they were back to the safety of the beach.

    The rescuers call it the Human Chain. But it was the deeply “human” aspect of the rescuers' cooperation（合作）that made it so astonishing and successful.

    The arm bones of women who lived 7,000 years ago show a surprising level of strength-even higher than today's professional athletes. that's according to a first-ever study comparing prehistoric(史前的) bones to those of living people. The finding suggests a revision of history- the everyday lives of prehistoric women were filled with hard labor, rather than just sitting at home doing lighter tasks while the men struggled and fought for life.

    Before the study, there are no clear records describing how our ancient ancestors lived. It can be easy to forget that bone is a living tissue, one that responds to the difficulties we put our bodies through, "said lead author Alison Macintosh."Physical force and muscle activity both put pressure on the bone. The bone reacts by changing in shape, thickness and other aspects over time.

    Previous studies only compared female bones to contemporary male bones, the researchers said-and that's a problem, because the response of male bones to stress and change is much bigger than that of women. For instance, as humans moved from a hunter-gatherer lifestyle constantly on the move to a more settled agrarian(农耕的) one, changes can be observed in the structure of the shinbone(胫骨)- and these changes were much more evident in men.

    However, a comparison of the bones of prehistoric women to the bones of living female athletes can help us work out a more accurate picture of what those prehistoric women were doing. "By analyzing the bones of living people and comparing them to the ancient bones, we can start to explain the kinds of labor our ancestors were reforming, Macintosh said. What they found was that women's leg strength hasn't changed a great deal, but their arms used to be very powerful. Prehistoric women, the researchers found, had arm strength 11-16 percent stronger than those of modern rowers, and 30 percent stronger than those of non-athletes.

    I'll never forget the day when Mary came into my office and said, I am too old to learn how to use a computer. I shook my head. Here was a woman who had raised 6 children and who had made great progress in her career telling me that she was too old to learn something new. I told her that I always believed people were never too old to learn.

    Mary followed my advice and did learn how to use the computer. Now, she is retired and leading a very active life volunteering in her community( 社区 ),using her computer skills and helping anyone that needs help.

    When she was in her sixties, one day she called me and said she had played the piano for others all her life, and now she was going to make a CD of her own. My mind flashed back to the day when she told me she was too old to learn. You can imagine my surprise and delight.

    To produce the CD, she had a lot of things to learn. It was not just sitting at the piano and playing. She had to research the songs, learn about copyright(版权),and learn about marketing. It was pretty amazing for someone who once said she was too old to learn. And finally she made it. Now she has her own CD-Mixed Blessings.

    Most of you probably have heard about some people who have gone back to university in their seventies and have also graduated. They are on their way again to charging themselves with a new skill and a new attitude towards life. The point is you are unable to learn anything at any age if you believe you are too old. On the contrary, you can achieve anything at any age if you believe you can.

    Have you ever been faced with trying to stay positive when others around you are negative? A negative person can bring you down and throw your positive plans out of the window. Whether you deal with a family member, friend or co-worker who is negative, there are things you can do to remain positive in the face of negativity?

    Whatever you do, don't argue with a negative person. Arguing only adds fuel to the fire. I have noticed when my children are crabby, it is best to avoid trying to ask them to analyze and adjust their attitude. As soon as I take the approach of being in opposition to them, the situation gets worse before it gets better. Sometimes the best thing to do is remain silent and let negativity pass.

    You know how difficult it can be to give love and positive attention to negative people. Unfortunately, that is often exactly what they need. A negative person is usually afraid he is unlovable. How do you show love when someone is negative? You must listen to what he is trying to tell you. Acknowledge the feelings he has by saying something like, "You sound very angry right now." How might you help a negative person? Offer a hug even if you get rejected. A negative person often has difficulty accepting love from others.

    If you have negative people on your life who are affecting your mental and physical health, you need to decide whether or not you want these people in your life. Some people are so negative that you have no other choice but to separate them from your life. However, some people, such as your children, are difficult to remove from your life, in this case, professional counseling(咨询) may be the answer.