Food from the air

    Everyone has seen plants growing, but have you ever thought {#blank#}1{#/blank#} they get their food? In the seventeenth century, a European scientist {#blank#}2{#/blank#} (call) Van Helmot asked this question. Like most people, he thought that plants must get their food from soil. However, Van Helmot decided {#blank#}3{#/blank#} (test) the theory with experiments.

    First, he dried some soil, put it into a pot and weighed it. Next, he weighed a small tree, planted it in the pot and added rain water. Then, he watered it {#blank#}4{#/blank#} (regular) with rain water.

    After five years, he removed the tree from the pot and weighed it again. He found that the tree had gained {#blank#}5{#/blank#} huge amount of weight. When he weighed the soil, however, it was almost exactly the same as it had been five years {#blank#}6{#/blank#}. So Van Helmot drew the {#blank#}7{#/blank#} (conclude) that the tree grew by drinking water. Though it turned out to be wrong, he showed the importance of the use of scientific evidence to support ideas.

    We now know that plants and trees make their own food. Their leaves, when exposed {#blank#}8{#/blank#} the air and sun, are like factories {#blank#}9{#/blank#} can change the energy from the sun into chemical energy. During this process (过程), oxygen and sugar {#blank#}10{#/blank#} (produce). The oxygen is released back into the air, and the sugar is used by the plant as food.

    As a stranger in Atlantic City, I often used to go walking outside. One afternoon, I found a little boy{#blank#}1{#/blank#} (stand) alone, and he looked very lost. I tried to get his trust, so I{#blank#}2{#/blank#}(buy) him an ice-cream cone and decided to call the police to take him home. I told{#blank#}3{#/blank#} to stay there when I went to the phone booth(电话亭), {#blank#}4{#/blank#} after I returned, he was missing. A few minutes later, {#blank#}5{#/blank#} patrol car arrived. The policeman asked me {#blank#}6{#/blank#} the child was. I felt stupid; {#blank#}7{#/blank#} was embarrassing (难堪的) to say that I had lost a lost child. I told the policeman {#blank#}8{#/blank#} had happened and gave him a {#blank#}9{#/blank#}(describe) of the boy. "What did you treat him with?" he asked. "An ice-cream cone. Why?" "That kid lives only a few blocks {#blank#}10{#/blank#} here, and you're about the fifth stranger he's conned (欺骗) for a treat!"

    Xie Lei, a Chinese student studying in Britain, shared her progress in both study and life. It was the first time she {#blank#}1{#/blank#} (leave) her motherland. On arriving in London, she lived with a host family, in {#blank#}2{#/blank#} they always helped her. It's {#blank#}3{#/blank#} great comfort for her. And she is halfway through her {#blank#}4{#/blank#} (prepare) year, which is a must for any student before entering a degree course. But she found {#blank#}5{#/blank#} difficult to get used to the academic requirements of a western university, because she got an E for her first essay. When she asked the reason for the tutor's revision, the tutor said that she couldn't write {#blank#}6{#/blank#} other people said without {#blank#}7{#/blank#} (acknowledge) them and encouraged her to express her own ideas.

    Now Xie Lei feels much more at home in England. In other words, she adapts {#blank#}8{#/blank#} the new environment well. {#blank#}9{#/blank#} (hopeful), she is going to join a few {#blank#}10{#/blank#} (club) to make friends and have a balance between study and a social life.

    The term "extreme sports", which we might have seen on a magazine or a website, {#blank#}1{#/blank#}(be) becoming more and more common as the concept of extreme sports gains {#blank#}2{#/blank#} (popular). But what are extreme sports on earth?

    During the 1970s and 1980s, the term was used for sports with high risks {#blank#}3{#/blank#} (involve). Today, however, the sports also include activities that give a feeling of adventure without{#blank#}4{#/blank#}(necessary) putting a participant's life in danger. For every extreme sport, there is professional equipment that has been developed {#blank#}5{#/blank#} (protect) your body, improve your performance and give you{#blank#}6{#/blank#} advantage in the competition.

    Extreme sports cover a wide range. Some {#blank#}7{#/blank#} (develop) from familiar activities so far, like mountain biking, climbing and drag race. Some may not be well known. For instance, bouldering is a kind of rock climbing {#blank#}8{#/blank#} no rope is used. {#blank#}9{#/blank#} usually takes place in an area with large rocks or in climbing center.

    Nowadays, such sports have become more popular {#blank#}10{#/blank#} young people all over the world than ever before.

It is widely accepted that optimistic attitudes promote health as well as happiness. The secret of a long life is {#blank#}1{#/blank#} (universe) desired and has long been sought. Today we can reveal it: always look on the bright side. A huge research project {#blank#}2{#/blank#} (lead) by scientists at the Boston University School of Medicine concludes that optimists live {#blank#}3{#/blank#} (long).

Lewina Lee, lead author of the study, said, "A lot of evidence {#blank#}4{#/blank#} (suggest) that exceptional longevity(长寿) is widely accompanied by a longer span of good health and living {#blank#}5{#/blank#} disability. Therefore our findings raise an exciting possibility {#blank#}6{#/blank#} we may be able to promote health and happiness by {#blank#}7{#/blank#} (develop) positive attitudes such as optimism."

However, the study doesn't suggest that we should aim for great pleasure. Sadness is {#blank#}8{#/blank#} important part of the human condition. Any normal person sometimes experience disappointment, ambitions and the {#blank#}9{#/blank#} (lose) of loved ones. But for many people, these matters of human existence {#blank#}10{#/blank#} (transform) into an abnormal state of despair. There is a vital place in public health for providing mental treatment in helping to correct these cognitive errors. It is not weakness to be defeated by setbacks. It is merely a mistake.