America is a mobile society. Friendships between Americans can be close and real, yet disappear soon if situations change. Neither side feels hurt by this. Both may exchange Christmas greetings for a year or two, perhaps a few letters for a while — then no more. If the same two people meet again by chance, even years later, they pick up the friendship. This can be quite difficult for us Chinese to understand, because friendships between us flower more slowly but then may become lifelong feelings, extending (延伸) sometimes deeply into both families.

    Americans are ready to receive us foreigners at their homes, share their holidays, and their home life. They will enjoy welcoming us and be pleased if we accept their hospitality (好客) easily.

    Another difficult point for us Chinese to understand Americans is that although they include us warmly in their personal everyday lives, they don't show their politeness to us if it requires a great deal of time. This is usually the opposite of the practice in our country where we may be generous with our time. Sometimes, we, as hosts, will appear at airports even in the middle of the night to meet a friend. We may take days off to act as guides to our foreign friends. The Americans, however, express their welcome usually at homes, but truly can not manage the time to do a great deal with a visitor outside their daily routine. They will probably expect us to get ourselves from the airport to our own hotel by bus. And they expect that we will phone them from there. Once we arrive at their homes, the welcome will be full, warm and real. We will find ourselves treated hospitably.

    For the Americans, it is often considered more friendly to invite a friend to their homes than to go to restaurants, except for purely business matters. So accept their hospitality at home!

阅读下列短文，从每题所给的四个选项 （A 、B 、C  和 D ）中，选出最佳选项。

    In an ideal world, people would not test medicines on animals. Such experiments are stressful and sometimes painful for animals, and expensive and time-consuming for people. Yet animal experimentation is still needed to help bridge vast gaps in medical knowledge. That is why there are some 50 to 100 million animals used in research around the world each year.

    Europe, on the whole, has the world's most restrictive (严格的) laws on animal experiments. Even so，its scientists use some 12 million animals a year, most of them mice and rats, for medical research. Official statistics show that just 1.1 million animals are used in research in America each year. But that is misleading. The American authorities do not think mice and rats are worth counting and, as these are the most common laboratory animals, the true figure is much higher. Japan and China have even less comprehensive (全面的) data than America.

    Now Europe is reforming the rules governing animal experiments by restricting the number of animals used in labs. Alternatives to animal testing，such as using human tissue or computer models, are now strongly recommended. In addition, sharing all research results freely should help to reduce the number of animals for scientific use. At present, scientists often share only the results of successful experiments. If their findings do not fit the hypothesis (假设) being tested, the work never sees the light of day. This practice means wasting time, money, and animals' lives in endlessly repeating the failed experiments.

    Animal experimentation has taught humanity a great deal and saved countless lives. It needs to continue，even if that means animals sometimes suffer. Europe's new measures should eventually both reduce the number of animals used in experiments and improve the way in which scientific research is conducted.

    Twelve years ago, I was a 19 -year-old guy living in the French A1ps. In February 2004, while skiing the back - country in Val d'Isere, I fell off the mountain, resulting in a right leg broken in several pieces. I was helicoptered to hospital, operated on immediately—and there started my adult life.

    Before the accident, I was on a path to what I hoped would be a career in rugby. After-wards, and participation in collision sport was gone. I found a replacement in cycling. Unfortunately, by late 2012, I tried to cycle up Mount Ventoux, but it was halfway up when the pain hit me and I gave up.

    A decision needed to be made on a next step. I had to have my lower right leg cut off. Several months later, I had my first proper weight - bearing prosthetic (假肢). I jumped on a train with my bike to Mount Ventoux. Though it certainly wasn't my quickest, I did it.

    Two weeks later, I was lucky enough to be given a running blade; I bounced on it that day and then raced my triathlon (三项全能) on the Monday. So, that was me, up and running - almost 12 years since I had last run.

    Along with my running coach, I complete a “make every kilometre count” programme of four runs per week alongside a busy cycle, swim and gym schedule. So far this year, I have raced a 10k with an unexpected personal best in January of 38:04. I have my first speed triathlon in late March before heading to North Korea to compete in the Pyongyang Marathon on 10 April.

    If my lifetime allows, I will attempt to race in every country in the world. In the meantime, I'll keep on running — and, when it hurts and I'm low on motivation, I'll remember how far I've come and how much further I've got to go.

    The world's first-known nursery for baby giant manta rays(蝠鲼) has been discovered hidden away in the Gulf of Mexico, the place of 70 miles off the coast of Texas, after studying decades of giant manta ray data from the area by the scientists.

    Where the baby manta rays grow up has long troubled scientists, as they are rarely spotted in the four to five years it takes them to become adults, when they can often grow to more than 20ft wide.

In the study Mr Stewart and colleagues describe a reef (暗礁)—filled with mantas of all ages—where the sea floor runs down into deeper water. He said "We think they may be feeding on specific types of zooplankton(浮游生物) there, then migrating up toward the surface, where we saw them. They might be hanging around the banks because it could be a little safer than open water. We've seen them so rarely that we know very little about these baby manta rays. We don't know how far they move, or exactly what they feed on, or all of the habitats these access.”

    Giant manta rays are listed as species dying out by protectors, although actual population numbers of the mysterious "gentle giant" are hard to calculate. Sightings of the closely-related reef manta, however, have dropped by 90 percent in regions of southeast Asia in the past decade, according to a study.

    Fishing is considered the biggest threat to giant manta numbers, both intentional and accidental. Their gill plates(腮下肉)- the parts through which they filter(过滤) their food from seawater-are sold in China for medical purposes, while they often end up as something caught by mistake due to their huge wings.

Welcome to your future life!

    You get up in the morning and look into the mirror. Your face is firm and young-looking. In 2035, medical technology is better than ever. Many people at your age could live to be 150, so at 40, you're not old at all. And your parents just had an anti-aging(抗衰老的) treatment. Now, all three of you look the same age!

    You say to your shirt, "Turn red." It changes from blue to red. In 2035, "smart clothes" contain particles(粒子) much smaller than the cells in your body. The particles can be programmed to change clothes' color or pattern.

    You walk into the kitchen. You pick up the milk, but a voice says," You shouldn't drink that!" Your fridge has read the chip (芯片) that contains information about the milk, and it Knows the milk is old. In 2035, every article of food in the grocery store has such a chip.

    It's time to go to work. In 2035, cars drive themselves. Just tell your "smart car" where to go. On the way, you can call a friend using your jacket sleeve. Such "smart technology" is all around you.

    So will all these things come true? "For new technology to succeed," says scientist Andrew Zolli," it has to be so much better that it replaces what we have already." The Internet is one example what will be the next.

    A new study shows students who write notes by hand during lectures perform better on exams than those who use laptops.

    Students are increasingly using laptops for note-taking because of speed and legibility(清晰度).But the research has found laptop users are less able to remember and apply the concepts they have been taught.

    Researchers performed experiments that aimed to find out whether using a laptop increased the tendency to make notes "mindlessly" by taking down word for word what the professors said

    In the first experiment, students were given either a laptop or pen and paper .They listened to the same lectures and were told to use their usual note-taking skills. Thirty minutes after the talk, they were examined on their ability to remember facts and on how well they understood concepts.

    The researchers found that laptop users took twice as many notes as those who wrote by hand. However, the typists performed worse at remembering and applying the concepts. Both groups scored similarly when it came to memorizing facts.

    The researchers' report said, "While more notes are beneficial, if the notes are taken mindlessly, as is more likely the case on a laptop, the benefit disappears."

    In another experiment aimed at testing long-term memory, students took notes as before but were tested a week after the lecture. This time, the students who wrote notes by hand performed significantly better on the exam.

    These two experiments suggest that handwritten notes are not only better for immediate learning and understanding, but that they also lead to superior revision in the future.