We all know that exercise is good for your health. But some kinds of exercise may be better than others. Running for example, may help to protect us {#blank#}1{#/blank#}heart disease and other health problems. Running also may help you live {#blank#}2{#/blank#}(long).

    Recently, researchers studied more than 55,000 adults. About one-fourth of the adults reported running{#blank#}3{#/blank#}(regular). The study found these runners were considerably less likely than non-runners{#blank#}4{#/blank#}(die)of any form of disease, including heart disease.

    D. C. Lee and the other researchers found that speed,{#blank#}5{#/blank#} (distant)and how often one runs made little difference in{#blank#}6{#/blank#}(reduce)the risk of death. The runners in the study averaged between 10 and 16 kilometers per hour. Mr. Lee says slower runners, and those who only ran once{#blank#}7{#/blank#}twice a week, were helped nearly as much as those who ran faster and further.

    The researchers note that their study{#blank#}8{#/blank#}(base) on the participants' answering questions over the years. The study lacked complete information on {#blank#}9{#/blank#}these men and women ate and other facts about their lifestyles.

Researchers say this missing information could have affected the results. Still they hope their findings will motivate healthy adults to start running, a bit, down the road to live{#blank#}10{#/blank#}longer life.

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.

In 1990, over 100 countries signed {#blank#}1{#/blank#} international agreement to make it illegal to buy or sell ivory, which is mainly used for jewelry. Most ivory is made from the tusks(象牙) of African elephants. These tusks are {#blank#}2{#/blank#}(terrible) valuable—one pair is worth more than three times the income of an African farmer or a factory worker in a year.

    Hunting elephants was so profitable {#blank#}3{#/blank#}from 1979 to 1989 the number of elephants in Africa fell from 1.3 million to 600,000. It was feared that by the year 2020 there would be none {#blank#}4{#/blank#}(leave). However, thanks{#blank#}5{#/blank#} the international agreement, there {#blank#}6{#/blank#}(be) much less illegal hunting since 1990.

    But considering {#blank#}7{#/blank#}(vary) of aspects, it costs a lot of money to preserve elephants. Games wardens (看守人) must be hired to protect them. Land must be set aside for them, and when they destroy a farmer's crops, the farmer must {#blank#}8{#/blank#}(pay) compensation.(赔偿金)

    Zimbabwe and four other African countries say that some of the elephants should be killed legally. This would help keep the population stable, and selling the ivory would help pay for preserving the elephants. But conservationists say that {#blank#}9{#/blank#}(make) ivory legal to sell would lead to even more illegal hunting. Others say {#blank#}10{#/blank#}is wrong is to kill elephants because they are sensitive animals that feel emotional pain at the death of other elephants.

    Digital receipts offer a few improvements over {#blank#}1{#/blank#}(tradition) paper receipts. One is health-related. Lots of receipt paper contains bisphenol—A, or BPA. This chemical can completely influence or outright change some bodily processes, like hair growth, hormone function and cell repair. {#blank#}2{#/blank#} (reduce) receipt paper reduces the risk for BPA exposure for not only consumers but also for employees who handle the paper {#blank#}3{#/blank#} a more routine basis.

    Another reason why digital receipts are better just boils down to {#blank#}4{#/blank#} (convenient). You can access those receipts through your email and file {#blank#}5{#/blank#} (they) away in a separate folder or with a specific label for easy sorting. Or, if you need more help on the organization front, try a receipt tracking app. Physical receipts require you physically {#blank#}6{#/blank#} (keep) track of them, and that means a shoe box or an accordion folder or a big thumb tack on a cork board in the kitchen. There have been times when I've let something go unreturned {#blank#}7{#/blank#} I didn't have the receipt. I'm betting I'm not alone on that.

    Some businesses, particularly local ones, use newer point of sale systems like Square that will {#blank#}8{#/blank#} (automatic) send you a digital receipt if you've already received one from another business that uses Square. When you pay with the same credit you did at the first seller, and you've already provided {#blank#}9{#/blank#} email address to the Square system, you {#blank#}10{#/blank#} (get) a receipt in your email minutes later.

    A cheerful panda {#blank#}1{#/blank#} (call) Bing Dwen Dwen has been chosen as the Olympic mascot for Beijing 2022 Olympic Winter Games. The new Olympic mascot will serve as an ambassador (大使) for winter sports, {#blank#}2{#/blank#} (bring) joy to those who participate in and watch the Olympic Winter Games. "Bing" means ice and symbolizes purity and strength. "Dwen Dwen" relates to children and means {#blank#}3{#/blank#} (honest), health, liveliness and loveliness. The mascot represents the strength and willpower of athletes and will help to promote the Olympic spirit.