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.

    Dr. Michael Prager, a leading Botox expert, said that a growing number of women are developing something called “computer face”. He also mentioned that professionals who worked long hours in front of a screen were ending up with saggy jowls（颚骨下垂）,“turkey neck” and deep-set wrinkles（皱纹） on their forehead and around their eyes.

    The Botox expert said that, of all his clients, office workers were most likely to show premature （过早的）signs of aging. “ If you are one of the unfortunate people who frown（皱眉）while you are concentrating on the screen then, over time, you will inevitably（不可避免地） end up with frown lines.'' Dr. Prager said. “What is perhaps more surprising is the number of women with saggy jowls because they are sitting in one position for so long. If you spend most of the time looking down then the neck muscles shorten and go saggy, eventually giving you a second neck.”

    Dr. Prager, who has a practice near Harley Street in London, said he encourages his clients（客户） to put a mirror next to their computer so they can see if they are frowning at the screen. “When people are stressed or thinking hard about something, then they will often put on agrumpy（脾气暴躁的）face' without even knowing what they are doing. When my clients put a mirror next to their desk, they are often shocked by the angry, frowning face which stares back at them.”

    He said, “The women I am seeing at the moment have only been using computers at work for the last decade or so. But women in their 20s have grown up with them and use them for every single task. I think the problem is going to become much, much worse. In another ten years, they could be looking quite awful.”

    Dr. Prager said there were several simple steps which could avoid “computer face” such as regular screen breaks and stretching the neck muscles. And, of course, there was always Botox. He said that, after a couple of sessions of Botox, the habit of “grumpy face” could be broken.

    Among all the fast growing science and technology, the research of human genes, or biological engineering as people call it, is drawing more and more attention now. Sometimes it is a hot topic discussed by people.

    The greatest thing that gene technology can do is to cure serious diseases that doctors at present can almost do nothing with, such as cancer and heart disease. Every year, millions of people are murdered by these two killers. And to date, doctors have not found an effective way to cure them. But if the gene technology is applied, not only these two diseases can be cured completely, bringing happiness and more living days to the patients, but also the great amount of money people spend on curing their diseases can be saved, therefore it benefits the economy as well. In addition, human life span （寿命） can be prolonged.

    Gene technology can help people to give birth to more healthy and clever children. Some families, with the English imperial （皇家的） family being a good example, have hereditary diseases. This means their children will for sure have the family disease, which is a great trouble for these families. In the past, doctors could do nothing about hereditary diseases. But gene technology can solve this problem perfectly. The scientist just need to find the wrong gene and correct it, and a healthy child will be born.

    Some people are worrying that the gene research can be used to manufacture human beings in large quantities. In the past few years, scientists have succeeded in cloning a sheep, therefore these people predict that human babies would soon be cloned. But I believe cloned babies will not come out in large quantities, for most couples in the world can have babies in very normal way. Of course, the government must take care to control gene technology.

    It was five years since I had become a mother, and I felt like I had slowly been losing more and more of myself. I looked in the mirror one morning and saw a tired, crazy woman, and I just wanted to cry. And just like that my new journey into becoming a “do less” mom began. I remember the first time I tried it. I had rushed to get my kids from school after work, arriving home completely shattered(散架了).

    I made myself a lovely cup of hot tea and headed to the sofa, I lay down and closed my eyes. At this point, all three of my kids stopped speaking and just stared. My eldest broke the silence and asked, “What are you doing mommy?” I replied: “I'm resting.” It took the kids a few more minutes to realize I wasn't going anywhere and they did eventually leave me alone. They even figured out that they should probably take their coats off. I did not cook dinner that night--we ordered in. I did not put on a wash; instead, I told the kids they had better not get their clothes dirty during dinner because they are wearing them again tomorrow. We skipped the bath and watched a movie all on the sofa.

    To my amazement--no one died. The house did not fall apart. The kids were happy and fed but most importantly, when I looked into the mirror that night, I could see that woman I remember. The fun, silly woman who truly thinks she is still 25 years old, who loves ice cream and traveling and music and drinking wine. And I went to bed a bit happier that night knowing that although the road is still long, I am finally on the right track.

    The city of San Francisco is a wonderful tourist attraction that offers many different things to see and do. The best way for a traveler to get a good look at the city is to take one of the many different tours there

    Walk to Tour the City

    When touring the city by walking, you aren't going to walk much. What's more, there are far more benefits. This kind of tour allows you to see as many buildings of the city as possible. A tour of the city on foot usually focuses on a more localized neighborhood level, which can be very interesting in a number of different ways.

    Hit the Waters of San Francisco Bay

    The waters of San Francisco Bay have played an important role in the city's development over the last century. Touring San Francisco from the water is completely unique way for you to see this wonderful city.

    Take a Bus Tour

    If you want to see a wide variety of attractions from all over the city, one of the best things you could do is to book a tour through our company that offers services here. A bus tour of San Francisco is one of the most complete ways to experience the city

    Tour San Francisco From the Air

    While it is one of the most expensive ways to see San Francisco, touring the city from the air is one of the most unique and exciting ways to see the city. Seeing the city from high above allows you to get a full view of the city as tour guides point out attractions from high above. If you do decide to tour San Francisco by air, you'll be creating memories that you won't forget forever.

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    Food sometimes gets poisoned with harmful things. A person who eats such food can get an illness called food poisoning. Food poisoning is usually not serious, but some types are deadly. The symptoms of food poisoning usually begin within hours of eating the poisoned food. Fever is one of the most common symptoms.

    Certain microorganisms(微生物)cause most types of food poisoning. Bacteria and other microorganisms can poison eggs, meat, vegetables, and many other foods. After entering the body, these tiny living things release(释放)poisons that make people sick.

    Some chemicals can also cause food poisoning. They are often added to food while it is being grown, processed, or prepared. For example, many farmers spray chemicals on crops to kill weeds and insects. Some people may have a bad reaction to those chemicals when they eat the crops.

    Some plants and animals contain natural poisons that are harmful to people. These include certain kinds of seafood, grains, nuts, seeds, beans, and mushrooms.

    When people handle food properly, the risk of food poisoning is very small. Microorganisms multiply rapidly in dirty places and in warm temperatures. This means that people should never touch food with dirty hands or put food on unwashed surfaces. Food should be kept in a refrigerator to stop microorganisms from growing. Meat needs to be cooked thoroughly to kill any dangerous microorganisms. People should also wash food covered with chemicals before eating it. Finally, people should not eat wild mushrooms or other foods that grow in the wild. Some of these foods may contain natural materials that are poisonous to humans. In addition, some types of fish can be poisonous.

    Most people recover from food poisoning after a few days of resting and drinking extra water. If people eat natural poisons, they must go to the hospital right away to have their stomachs emptied.