The African elephant, the largest land animal remaining on earth , is of great importance to African ecosystem(生态系统). 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(栖息地).

    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 underbushes, 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.

    Cleverness is a gift while kindness is a choice．Gifts are easy—they're given after all．Choice can be hard．

    I got the idea to start Amazon 16 years ago．I came across the fact that the Internet usage was growing at 2300 percent per year．I'd never seen or heard of anything that grew that fast，and the idea of building all online bookstore with millions of titles was very exciting to me. I had just turned 30 years old，and I'd been married for a year．I told my wife MacKenzie that I wanted to quit my job and go to do this crazy thing that probably wouldn't work since most start-ups don't and I wasn't sure what to expect．MacKenzie told me I should go for it．As a young boy，I'd been a garage inventor．I'd always wanted to be all inventor，and she wanted me to follow my passion．

    I was working at a financial firm in New York City with a bunch of very smart people and I had a brilliant boss that I much admired．I went to my boss and told him I wanted to start a company selling books on the Internet．He took me on a long walk in Central Park，listened carefully to me，and finally said，“That sounds like a really good idea，but it would be an even better idea for someone who didn't already have a good job．”That 1ogic made some sense to me，and he convinced me to think about it for 48 hours before making a final decision．Seen in that light,it really was a difficult choice，but finally，I decided I had to give it a shot．I didn't think I'd regret trying and failing．And I suspected I would always be haunted by a decision to not try at all.

    After much consideration ，I took the less safe path to follow my passion ，and I'm proud of that choice．For all of us，in the end，we are our choice．

    Most of us have quite good memories, but our memories are limited. For example, we cannot remember everyone we have ever met or what we did on every single day of our lives. However, there are some people who do have prodigious memories. These people have a rare condition known as savant syndrome（学者症候群）. Savants suffer from a developmental disorder, but they also exhibit great talents that contrast（显出差异）sharply with their physical and mental disabilities.

    Kim Peek (1951-2009) was a savant who lived in Salt Lake City, Utah, in the United States. He was born with damage to parts of his brain, but it seemed that other parts of his brain, particularly those relating to memory, became over-developed.

    Peek's unique abilities appeared at a very early age. When he was just 20 months old, he could already remember every book that was read to him. Peek could read two pages of a book at the same time-one page with the right eye and one with the left-in less than 10 seconds and remember everything he read. By the time he died, Peek had memorized more than 9,000 books. He could remember all the names and numbers in a variety of telephone books. He could remember thousands of facts about history, literature, geography and sports.

    Dr. David Treffert, an expert on savant syndrome, once described Peek as “a living Google” because of his astonishing ability to memorize and connect facts. However, at the same time, Peek was unable to carry out simple tasks, such as brushing his hair or getting dressed, and he needed others to help him. In 1989, the movie Rain Man won the Oscar for best Picture. The main character in the movie, played by Dustin Hoffman, was based on Kim Peek's life. He started to appear on television, where he would amaze audiences by correctly answering difficult questions on different topics. Peek-became world famous, and he and his father began touring widely to talk about overcoming disabilities. He inspired a great many people with his words. “Recognizing and respecting differences in others, and treating everyone in the way you want them to treat you, will make our world a better place for everyone. Everyone is different.”

    I found the last outdoor table at my favourite cafe. Reading as I ate my breakfast slowly, I was enjoying the feeling of the cool wind and the warm sun when a table next to me opened up. A woman, who had been standing nearby, clearly waiting for a seat, stepped towards the table. But from the other direction, straight from the parking lot, came a man who got to the table first.

    The woman, with a smile on her face, explained that she'd been keeping her eye on that table for several minutes and had been on her way over. The man, also smiling but determined, told her she was out of luck.

    She stood off the side, clearly disappointed, and greeted her friend with the disappointing news. I sat at my table, taking in the scene, and suddenly I realized that I had an opportunity to be kind.

    I stood up and asked her to come to my table. Quietly, I told her I had seen what had happened, and I was happy to give her my table. I was only going to be there a few more minutes anyway, so I was happy for her and her friend to have the seat.

    "But where will you sit?" she asked. I was almost done eating, I said, and I would find a seat at the counter (柜台) inside. She thanked me and beamed with delight as she invited her friend to sit down.

    Thinking about it as I finished up, I realized that whether or not the woman had acceptable demand for the table was unimportant. The feeling of the situation -- the look of hurt on her face -- had struck me, and I had the ability to do something about it.I just hope that woman's morning at the cafe was great. I know mine was.

    Losing a wallet is one of those careless acts most of us have come across, at some point or the other in our lives. While most of us tend to move on after mourning over the lost necessities, there are a few lucky ones who get them back, with the help of the police or the generosity of the person who finds it.

    And then there is Hunter Shamatt, who not only got back his wallet but with some added happiness that was tagged along!

    Hunter was on his way to attend his sister's wedding on a Las Vegas-bound flight when he realized that he has misplaced his wallet, sometime during the journey. Hunter's family reached out to the Frontier flight to enquire if someone had handed it over to them. Unfortunately, there was no sign of the missing wallet.

    But wait. The story was far from over. Just a week after Hunter's sister's wedding, he received a package in his mail. And guess what? There was his wallet! Surprisingly, the wallet was not the only thing that was inside the package. It also had a handwritten note for Hunter which turned out to be a bonus! The piece of paper read,

"Hunter, Found this on a Frontier flight from Omaha to Denver — row 12, seat F wedged between the seat and wall. Thought you might want it back. All the best.

P.S. I rounded your cash up to an even $100, so you could celebrate getting your wallet back. HAVE FUN!!!"

    Moved by the touching gesture, Hunter's mom, Jeannie Shamatt, decided to write a post on Facebook giving a detailed description of the incident. She also urged everyone to share the post as she would like to meet and greet the person behind the act of kindness, personally.

    Now, thanks to the astonishing power of social media, the post finally reached the man behind the note. The man was identified as Todd Brown and it was one of his co-workers who made sure Jeannie Shamatt's post reaches his colleague. Jeannie turned to Facebook again to thank Brown and his family for restoring her faith in humanity.

    "I try to teach my children to do the right things in life, help people when you can regardless of the outcome. This story is more about restoring faith in people than anything. We hear a lot of bad news but not enough good news. I personally want to thank Todd Brown and his wife for restoring faith that there are amazing people out there."

    On the banks of Tanzania's Lake Eyasi lives the world's last hunter-gatherer tribe (部落) — the Hadza. They don't grow food, raise animals or build houses. Instead they live a life unchanged for more than ten thousand years.

    Their world is one of complete freedom — something modern society can barely imagine and is unlikely to ever experience, let alone have the skills to stay alive. Text messages and phone calls don't exist. Nor do cars and electricity. No jobs, timetables, and social structures. No laws, taxes and unbelievably, no money — the closest thing to currency (交易) is the trade for a pair of shorts with a neighboring tribe.

    We spent our time with the Hadza hunting baboons (狒狒), a daily activity for the men. Their land is packed with sharp bushes, poisonous snakes and man-eating lions. But a successful hunting trip is the difference between eating or going hungry.

    The Hadza diet consists mainly of honey, fruit and meat. Men often hunt in pairs to shoot animals with bows and arrows. The Hadza show us how to track animals, from baboons to snakes to lions. They are hugely skilled with their handmade bows and arrows — we have a go and barely get the arrow to go three feet in front of us.

    The language of the Hadza is believed to be the oldest still-spoken language known to man. The Hadza don't have conflict, and have no memory of starvation. Their population never reaches numbers that cannot be supported through hunting or gathering. They never get from their land more than they need.

    Unlike modern-day office workers, the Hadza enjoy an extraordinary amount of free time. Their “work” — hunting for food — takes up around five hours of their day. They've been in such a state of peaceful existence for thousands of years.