I used to believe courtesy(礼貌) was a thing of the past. Very seldom have I encountered a courteous human being in this modem era of the so called Generation X.

    Recently, I had to change my thinking, when I came face to face with just such a human being. I had gone to a happening coffee place, with two of my grown up daughters. The place was crowded with the usual loud crowd and we had to climb a sleep flight of stairs in order to find an empty table. After enjoying coffee and snacks, we were at the steep descent down the stairs, where the narrow space made climbing down only possible in a single file, with hardly any space for another person to either climb up or come down.

    Just as I was in the middle of my descent, a gentleman entered the main entrance of the restaurant which right in front of the staircase. I was sure I would be pushed roughly by this man who will want to go up in a hurry. I kept coming down as fast as I could, holding on to the banister (栏杆), instead of my advanced years. My agile daughters were already down, looking up at me worriedly, hoping I would reach them before the stranger strange started up the stairs, knowing I was a nervous sort.

    Nearly reaching them, I noticed the man still standing near the door. I reached my daughters and passed the stranger at the entrance door which he kept holding open. I looked back thinking he was still at the door, deciding whether to go in or find another less crowded place. I saw him going up the stairs, two at a time. I told my daughters about it and all three of us felt had that we did not even thank the courteous gentleman who was actually holding the door open for us ladies to pass through before going up.

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。

Look into hunters' eyes

    Have you ever been face to face with a cat or a sheep? If you have,you probably noticed that cats narrow their eyes to vertical (垂直的) slits (狭缝),while sheep have horizontal pupils (瞳孔).

     Why is the difference?

    Scientists from the Universities of California Berkeley and Durham in Britain may have the answer. Their research, published recently in the journal Science Advances, suggested that pupils' shapes could tell whether an animal is a hunter or gets hunted.

    The researchers took a close look at the eyes of 214 land animals.The challenge was to see if they could find a relationship between an animal's role in the food chain and the pupils' shapes.

    They found a pattern. Species with pupils that are vertical slits are more likely to be small ambush predators (捕猎者) – creatures that lie in wait for their lunch.In contrast,those with horizontal pupils are more likely to be plant-eating prey (猎物) species.

    Evolution chose the arrangement for a good reason.For hunters such as household cats,it appears that vertical pupils not only improve their ability to keep track of moving objects like mice,but also maximize (使最大化) their ability to judge the distances of the animals they hunt.

    However, an interesting discovery from the study is that the slit pupils are mostly linked to hunters that are close to the ground. Therefore, bigger cats who actively hunt down their prey, like tigers and lions, don't have slit pupils.

    On the other hand, for plant-eating prey animals, horizontal pupils give them a wider field of vision.When stretched (伸展) horizontally,the pupils allow for more light to enter from the front, back, and sides. Meanwhile, they also limit the amount of light from the sun above so the animal can see the ground better.“ Once they do find a predator,they need to see where they are running,” said leading researcher Martin Banks,a UC Berkeley professor of optometry (视光学).“They have to see well enough out of the corner of their eye to run quickly and jump over things.”

    But what happens when they bend down to eat? Researchers checked this by watching prey animals in the Oakland Zoo in California, US. They believe that when goats lower their heads to eat,their eyes rotate (旋转) to keep their pupils horizontal.

    So it seems that the eyes are indeed the window to the soul!

    A great white shark in a California aquarium attacked two soupfin sharks(翅鲨), causing their deaths. The attack was not a natural action for food, but a kind of response when the two sharks swam too close to the great white. The great white didn't attacked other fellows, but the officials had to move other soupfin sharks to another tank(贮水池)for their safety.

    These attacks had given rise to calls for the freedom of the 88-pound, 5-foot-3- inch shark. The aquarium housed the shark in a huge tank. However, according to experts, the tank was not big enough for the shark. Its nose was bloody from striking the glass of the aquarium. Great white sharks in the wild had a big amount of migration, sometimes traveling 50 miles a day. Because the shark was still young, there was possibility of his growing. As it grows, it can became more troubled in the limited space.

    Aquarium officials said that keeping the shark in the aquarium allowed them to study their behavior that they cannot study with free great white sharks. When they studied behavioral patterns, scientists believed that they can help great white sharks in the wild.

    Since the shark had been on display, the number of people who visited aquarium increased greatly. The one-year-old shark was the longest surviving great white living here. It had been at the Monterey Bay Aquarium for six months. Other great whites did not survive for longer than 16 days in the aquarium.

    Are people less happy or more happy the older they get? A study found that people generally become happier and experience less worry after age 50. In fact, it found that by the age of 85, people are happier with their life than they were at 18.

    The finding came from a Gallup survey of more than 340,000 adults between the age of 18 and 85 in the United States.

    Arthur Stone in the Department of Psychiatry and Behavioral Science at Stony Brook University in New York led the study. His team found that levels of stress were highest among adults between the ages of 22 and 25. Stress levels dropped sharply after people reached their fifties.

    Happiness was highest among the youngest adults and those in their early seventies. But the people least likely to report feeling negative emotions were those in their seventies and eighties. The survey also found that men and women had similar emotional patterns as they grow older. However, women at all ages reported more sadness, stress and worry than men did.

    The researchers also considered possible influences like having young children, being unemployed or being single. But they found that influences like these did not affect the levels of happiness and well-being related to age.

    So why would happiness increase with age? One theory is that, as people get older, they become more thankful for what they have and have better control of their emotions. They also spend less time thinking about bad experiences.

    The original goal of the study was to confirm the popular belief that aging is connected with increased sleep problems. The survey did find an increase during middle age, especially in women. But except for that, people reported that they felt their sleep quality improved as they got older.

A simple gesture can be formed into a child's memory so quickly that it will cause the child to give a false answer to a question accompanied by that gesture. A new finding suggests that parents, social workers, psychologists and lawyers should be careful with their hands as well as their words. 

Gestures can be as informative as speech, but hand gestures are so common that we rarely notice we're using them. 

While the recall of both adults and children are easy to react to suggestion, the memories of children are known to be particularly influenced, said lead researcher Sara Broaders of Northwestern University. Kids are used to looking to adults to tell events for them and can be misled even if not intentionally(故意地). 

Previous research, for example, has shown that detail-loaded questions often cause false answers; when asked, say "Did you drink juice at the picnic?", the child is likely to say "yes" even if no juice had been available. It is not that the child is consciously lying, but rather the detail is quickly formed into his or her memory. 

To avoid this problem, social workers have long been advised to ask children only open-ended questions, such as "What did you have at the picnic?" But an open-ended question paired with a gesture, briefly meaning a juice box, is treated like a detailed question. That is, children become likely to answer falsely. 

And it isn't just a few kids: 77% of children gave at least one piece of false information when a detail was suggested by an ordinary gesture. Gestures may also become more popular when talking with non-fluent language users, such as little kids, Broaders said as hand movements can impart meaning of unfamiliar words and phrases. "It certainly seems reasonable that adults would gesture more with children. "

In general, Broaders advises parents and other adults to "Try to be aware of your hands when questioning a child about an event. Otherwise, you might be getting answers that don't reflect what actually happened. "