The African elephant, which is the largest land animal remaining on earth, is of great importance to African ecosystem. Unlike other animals, the African elephant is to a great extent the builder of its environment. As a big plant-eater, it largely shapes the- forest-and-savanna (大草原) surroundings in which it lives, therefore setting the terms of existence for millions of other animals that live in its habitat.

    It is the elephant's great desire for food that makes it a disturber of the environment and an important builder of its habitat. In its continuous search for the 300 pounds of plants it must have every day, it kills small trees and under-bushes, and pulls branches off big trees. This results in numerous open spaces in both deep tropical forests and in the woodlands that cover part of the African savannas. In these open spaces are numerous plants in various stages of growth that attract a variety of other plant-eaters.

    Take the rain forests for example. In their natural state, the spreading branches overhead shut out sunlight and prevent the growth of plants on the forest floor. By pulling down trees and eating plants, elephants make open spaces, allowing new plants to grow on the forest floor. In such situations, the forests become suitable for large hoofed plant-eaters to move around and for small plant-eaters to get their food as well.

    What worries scientists now is that the African elephant has become an endangered species. If the elephant disappears, scientists say, many other animals will also disappear from vast areas of forest and savanna, greatly changing and worsening the whole ecosystem.

    Devon, 17, is used to paying her own cell phone and car expenses. But lately it's been harder. The family she baby-sits for hasn't been calling as much as usual and she couldn't find a job over the summer. Devon's dad said it's a sign of the tough economy. He told her he's feeling the pinch too and that he had to use her college fund to pay the loan(货款).

    This kind of money troubles isn't strange to common families these days. In fact, it's hard to avoid news about the economy on the screen of the TV or the computers recently. It can seem a bit worry and some families are hit really hard.

    For most people, the big problem is that things cost more at a time when they have less money to spend. But higher prices aren't the only problem. Many people are having a tough time making payments on some types of home loans.

    Therefore, some families are cutting back on what they spend.  For example, eating out less, staying home instead of going on vacation, moving to a less expensive house and so on.

    However, as discouraging as things may seem now, the good news is that the economy always gets back on track after a while. Jobs may be hard to find, but the slow economy can open up new opportunities. The couple Devon babysat for might cut back on evening's out, but they could be interested in hiring her for after-school care. Perhaps it's time to sell her old toys and baby gear (设备)in the basement(地下室) or help others sell these items online if she is good at it. She could charge them a fee to sell their old stuff(东西).

    When I was ten years old I went to the USA to visit some family friends. I noticed something funny about the way everyone spoke English.

    One moment! I remember very clearly was at the beginning of the holiday, when my friend asked me if I wanted to order “French fries”. I couldn't imagine what they were. She was amazed that I had never tried them and she ordered a portion for us to share. When the waiter brought us some chips, I asked her where the French fries were. She pointed at the plate of chips! Later that week she said she was going to buy some “chips” from the supermarket. She came out with a packet of crisps（薯片）! How come?

    During that holiday we were also offered “biscuits” with our lunch. This was a very strange idea to me, because in England biscuits are sweet. I later realized that “biscuits” in America are salty snacks. What we call “biscuits', they call “cookies”.

    I was also embarrassed when a stranger told me she liked my “pants”. I wondered how she could see them! My mum then told me that they call “pants” what we call “trousers”, the outer clothing that you wear on your legs instead of inside clothing!

    I was disgusted when I saw an “eggplant” pizza on the menu in a restaurant. But I was puzzled how eggs can grow on plants. My dad ordered this pizza and it was covered in aubergines（茄子）. “They call aubergines 'eggplant' in America!” he told me.

    I think part of the excitement of learning a language is learning about the differences that exist in how it is spoken in different places.

    It's really true what people say about English politeness: it's everywhere. When squeezing past someone in a narrow aisle, people say "sorry". When getting off a bus, English passengers say "thank you" rather than the driver. In Germany, people would never dream of doing these things. After all, squeezing past others is sometimes inevitable, and the bus driver is merely doing his job. I used to think the same way, without questioning it, until I started travelling to the British Isles and came to appreciate some more polite ways of interacting with people.

    People thank each other everywhere in England, all the time. When people buy something in a shop, customer and shop assistant in most cases thank each other twice or more. In Germany, it would be unusual to hear more than one thank you in such a conversation. British students thank their lecturers when leaving the room. English employers thank their employees for doing their jobs, as opposed to Germans.

    Another thing I observed during my stay was that English people rarely criticize others. Even when I was working and mistakes were pointed out to me, my employers emphasized several times but none of their explanations were intended as criticism. It has been my impression that by avoiding criticism, English people are making an effort to make others feel comfortable. This also is showed in other ways. British men still open doors for women, and British men are more likely to treat women to a meal than German men.

    It was only a dollar. Belscher noticed it on the floor as he sat at the back of his English class. When the school day ended, Belscher wandered back to the classroom. The old bill was still there. He could easily have pocketed it without thinking twice. Instead, he picked it up and brought it to his English teacher, Mattison.

    "It wasn't my money," Belscher says. Mattison was a little surprised he'd turned the dollar in, knowing a lot of people would have just kept it. She suggested that Belscher tape(贴) it to the whiteboard at the front of the classroom, where she always puts lost things.

    Rose, another student, was in English class after break when he spotted the dollar on the whiteboard. After class, he asked Mattison why it was there. She was still waiting for the original owner to claim it, so she replied, "I don't know." Rose took the tape from Mattison's desk and taped a second dollar to the board.

    That got it rolling. The sight of the two dollar bills, side by side, started something in Mattison's students. They started asking about the purpose of the money, to which Mattison always gave the same answer: She didn't know. At that point, it was true.

    More students, curious, taped up single dollar bills. Mattison started to leave the tape on the tray of the whiteboard. The effort snowballed. Even with no clear purpose, many students wanted to be part of whatever this was. The amount continued to grow over several weeks, until it reached $175.76.

    That left Mattison to make the best decision. She kept thinking about her brother-in-law, Jack Hains. Eight years earlier, Jack had died of amyotrophic lateral sclerosis (ALS), a rare and devastating neurological disease(神经疾病).

    Mattison explained to her classes that Jack had raised money every spring for the ALS Therapy Development Institute, established to seek a cure for the disease. She asked the teens whether they minded if she donated the dollars in their names in honor of Jack.

    Their answer was to tape enough money to the whiteboard over the next few days to push the amount to $321.06. Mattison, choking back tears as she recalls the moment, says she carefully picked the cash off the board and made the donation just before the beginning of May, which is National ALS Awareness Month. That was Saturday. By Monday afternoon, eight more dollars had been taped to the board.

Harvard Pre-College Program

    Our summer program for high school students is designed to pave the way for a successful college experience.

    HERE YOU CAN:

    Learn without limits

    Pursue your interests in courses focusing on physics, law, writing, philosophy, and a dozen other subjects.

    Live at Harvard

    You will live in a historic undergraduate house near Harvard Square.

    Your plan covers three meals a day, seven days a week.

    Have fun outside the classroom

    You might enjoy a Cirque du Sileil performance, a Red Sox game at Fenway Park, or a trip to the Museum of Science.

    ELIGIBILITY (申请资格)

    Students are academically motivated and will graduate in 2020 or 2021.

    TO APPLY

    Complete an online application and provide the following materials: the $50 nonrefundable application fee; transcripts (成绩单) with fall 2018 grades; signed rules and regulations.

    INTERNATIONAL STUDENTS

    Participants should apply for the B-2 tourist visa. If English is not your native language, submit scores from the TOEFLor IELTS language proficiency exam.

    APPLICATION TIPS

    No fee is required to start your application. You will be asked to pay the application fee only upon submitting the application.

    The scores of successful applicants are typically above 103 on the TOEFL with 25 on the written section or at least 7.5 on the IELTS with 7 on the written section.

    Use a desktop or laptop. You will be asked to write short essays as part of your application. This may be challenging to do on a mobile phone.

    You will receive an email informing you of the application status approximately three weeks after you have completed your application.