Since 2008, hunters have illegally killed more than 3000 rhinos in South Africa. The International Union for Conservation of Nature warns that rhinos may die out by 2026. People who hunt and kill illegally are called poachers. The most effective way to watch for and prevent illegal hunting is from the air. However, piloted flights are too costly. Fortunately, some Spanish college students have invented a drone (无人机) that can observe more places than a plane.

    Arnau Garcia is an aeronautical (航空学的) engineering student at the Polytechnic Institute of Catalonia, in Spain. He says observers from the air have trouble finding poachers when they hide under the trees. Mr. Garcia and other students have worked with the drone manufacturer HEMAV to help find the hidden poachers. They make it by using the thermal camera, which is especially sensitive to body heat. Even when the poachers keep still, it can also keep track of them.

    The drone can fly in the wind up to 55 kilometers per hour. It has an autopilot system, so it memorizes the flight path. The drone also has a microphone, a video camera and a GPS system. These permit it to report accurately where a picture is taken. After each flight, the drone can bring back detailed information about where rhinos are found, the conditions of water and plants in the area, and the positions of suspected poachers.

    Experts say the drone can fly as far as 70 kilometers from the base. It means that it could quickly observe large areas for poachers. However, the same search operation would take days for human observers. Thanks to the drone, many poachers have been caught and the number of rhinos is on the increase. In addition, HEMAV has received an increasing number of orders for the drone. Even South African national park officials attempt to fill the air with drones.

    Organic exercise is a good fit for people looking to train functionally. It is defined as exercise that is similar to the type of physical activity performed by ancient hunter-gatherer ancestors. Organic exercise is generally preformed in natural or outdoor settings. {#blank#}1{#/blank#} Organic exercise may include such activities as walking, jogging, swimming, hiking or rock climbing.

    When it comes to organic exercise, one of its most significant benefits is its limited reliance on equipment. {#blank#}2{#/blank#} Going for a jog, walking, or even hiking does not require tools, weights, or even hiking does not require tools, weights, or other products, and therefore, is fairly inexpensive.

    Since the types of activity emphasized in organic exercise programs are similar to those performed as part of daily life, they do not require extensive or long amounts of practice to obtain proficiency(精通). {#blank#}3{#/blank#} Therefore the type of activity recommended in an organic workout routine can be performed by beginning or advanced exercisers alike with relative ease.

    While the type of exercise recommended in an organic workout may be easy enough to perform, the intensity at which it is recommended can be too much for some individuals. {#blank#}4{#/blank#} Individuals who are new to exercise or suffer from a chronic health condition that limits their physical ability may find it difficult to perform exercise that is especially strenuous.

    {#blank#}5{#/blank#} Individuals who are new to exercise may want to talk with their health care provider before choosing this type of activity. In some cases, it may be better to start off with a more traditional workout and slowly transition to organic exercise than starting with this regimen(养生法)right off the bat.

A. Weigh both the benefits and drawbacks.

B. In fact, it can be done nearly anywhere, any time.

C. Therefore it requires very little helping equipment.

D. Choosing the right types of organic exercise is important.

E. Most adults already know how to hike, swim or dig, for example.

F. In fact, one of the biggest drawbacks is the emphasis on high-intensity exercise.

G. While organic exercise may be a good choice for some, it is right for all adults.

    Before the coming of the first settlers from Europe, Canada's local people had discovered a new kind of food—maple sap(汁液)，which they gathered every spring. According to many historians, the maple leaf began to serve as a Canadian symbol as early as 1700.

    In 1834, the first St. Jean Baptise Society in North America made the maple leaf its sign. In 1836, Le Canadian, a newspaper, referred to it as a suitable symbol for Canada. In 1860, the maple leaf was used widely in decorations for the visit of the Prince of Wales. Alexander Muir wrote The Maple Leaf Forever in 1867; it was regarded as the national song for several decades. The army uniforms created the next year for Ontario and Quebec both included the maple leaf. Later the maple leaf appeared on coins. Between 1876 and 1901, it appeared on all Canadian coins. The modern one-cent piece has two maple leaves on a common twig(细枝)，a design that has gone almost unchanged since 1937.

    During the First World War, the maple leaf was included on the badge(徽章) of the Canadian Expeditionary Force. Since 1921, the Royal Arms of Canada have included three maple leaves as a special Canadian symbol. In 1939, at the time of World War Ⅱ, many Canadian troops used the maple leaf as a special sign.

    With the announcement of Canada's new flag in 1965, the maple leaf has become the Canadian symbol. On February 15 of that year, the red maple leaf flag first appeared as the National Flag of Canada.

    In Africa, Christmas Day begins with groups of carolers (欢唱颂歌的人) walking to and from through the village, along the roadway, by the houses of the missionaries (传教士), singing the lovely carols known to the world around. Often people may be awakened by a group of carolers beginning to gather at the house of worship(敬神活动). They return home to make final preparations as to the clothes one must wear and also as to their offering for the Christmas service.

    The most important part of their Christmas worship service is the love offering. This is the gift in honor of Jesus. At about 8 or 9 o'clock everyone goes to the celebration of the birthday of Jesus. Everyone who attends the service goes forward to lay down their gift upon the raised platform near the Communion table. No one will attend the service without giving a gift.

    Christmas in South Africa is a summer holiday. There is no snow, but it has many flowers, many beautiful varieties of wild flowers being in their full pride.

    In Ghana, most churches show the coming of Christmas by decorating the church and homes beginning with the first week in Advent, four weeks before Christmas. This season happens to be the time of cocoa harvest, so it is a time of wealth. Everyone returns home from wherever they might be such as farms or mines.

    In Africa, it is the traditional dinner of turkey, roast beef, mince pies, or suckling pig, yellow rice with raisins, vegetables, and plum pudding, crackers. In the afternoon, families go out into the country and usually there are games or bathing in the warm sunshine, and then home in the cool of the evening. Boxing Day is also a proclaimed (正式宣布的) public holiday usually spent in the open air. It falls on December 26 and is a day of real relaxation.

    Mr. Guo is a teacher from Xi'an. He asked his students to hand in their homework through a QR code (二维码)."We spent an hour or two in class learning how to generate (使产生) the codes, and in the end everything gets easier." Said Guo, "When students finish the homework, they keep it on WeChat. Then, each student makes his own QR code and gives it to me. So I can check their work anywhere using my computer or telephone."

    The QR codes can be sent to Mr. Guo by email, QQ and WeChat. When Guo scans his students' QR codes, their homework appears on his phone. He finds that their homework becomes more creative, with many pictures, music and even videos.

    Guo's students like the new way and think it is interesting. "We are living in the information age. Many students like to work with computers, which makes learning more fun." said Tingting, a student of Guo's.

    "The paper is not easy to keep, but the code is easy to keep and share." Guo said, "It is worth trying to use new technology in education. Education itself is a kind of creation. I don't want my students to fall behind the times."

    However, some parents are worried. They are afraid that their children will spend too much time surfing the Internet and less time communicating with teachers. But in fact, it's unnecessary. Students still need to look up information in books and write it down when they do their homework. They only use the codes when they hand in their work, which doesn't take them too much time. Also for teachers, it allows them to check the students' work at any time. And it's also an easy way to share homework with other students.

    People who sleep fewer than six hours a night are more likely to die early, researchers in University of Warwick have found in a recent study. They discovered that people who slept for less than six hours each night were 12% more likely to die before the age of 65 than those who slept the recommended six to eight hours a night.

    The researchers pointed out that previous studies had shown that the lack of sleep was associated with problems like heart disease and high blood pressure. However, the researchers also found that sleeping too much was linked to an early death. Those who slept for more than nine hours a night were 30% more likely to die early, as an article in the latest Sleep suggested. That directly contradicts another passage in the same journal last month suggesting that people who slept for ten hours or longer a night were more likely to live to 100. This was thought to be because people who lived into extreme old age were healthier and therefore slept better.

    However, the authors of the latest research contradicted this and suggested that long sleep was a sign of underlying illnesses such as depression and low levels of physical activity. Professor Francesco Cappuccio at the University of Warwick said: "While short sleep may represent a cause of ill-health, long sleep is believed to represent more an indicator of ill-health."

    He also mentioned: "Modern society has seen a gradual reduction in the average amount of sleep people take, and this pattern is more common among full-time workers, suggesting that it may be due to social pressures for longer working hours. On the other hand, the worsening of our health is often accompanied by an extension of our sleeping time."

    "Consistently sleeping six to eight hours per night may be good for health. However, whether to achieve the goal depends on various factors such as the environment as well as measures of public health aimed at favourable changes of the working environments," Professor Francesco Cappuccio added.