1．The relationship between exercise and cancer has long both intrigued and puzzled oncologists and exercise physiologists． Exercise is strongly associated with lowered risks for many types of cancer．At the same time，exercise involves biological stress，which typically leads to a short-term increase in inflammation（发炎） which can contribute to higher risks for many cancers． Now，a new study in mice may offer some clues into the exercise-cancer paradox．It suggests that exercise may change how the immune system deals with cancer by boosting adrenaline（肾上腺素），certain immune cells and other chemicals that，together，can reduce the severity of cancer or fight it off altogether． To try to better understand how exercise can both elevate inflammation and simultaneously protect the body against cancer，scientists at the University of Copenhagen in Denmark and other institutions decided to closely examine what happens inside mice at high risk for the disease． So，for the new study，they began by gathering a group of adult lab mice．These animals generally like to run． The scientists then implanted melanoma（黑素瘤） skin cancer cells into the mice before providing half of them with running wheels in their cages while the other animals remained sedentary．After four weeks，far fewer of the runners had developed full-blown melanoma than the sedentary mice and those that had been diagnosed with the disease showed fewer and smaller lesions． They drew blood from both the exercising and sedentary animals and cells from any tumors in both groups．As expected，they found much higher levels of the hormone adrenaline in the blood of the exercising animals，especially right after they had been working out on the wheels but also at other times of the day．The body releases adrenaline in response to almost any type of stressful experience，including exercise． They also found higher levels of interleukin-6in the blood of the runners．This is a substance that is released by working muscles and is believed to both increase and decrease inflammation in the body，depending on where and how it goes to work． Perhaps most important，they found much higher numbers in the bloodstreams of runners than in the sedentary mice of a type of immune cell named natural killer cells that are known to be strong cancer fighters． So the scientists repeated their original experiment multiple times，inducing cancer while allowing some mice to run and others to sit．In some of these follow-up experiments，the scientists injected the runners with a substance that blocked the production of adrenaline and gave sedentary animals large doses of added adrenaline． What they now found was that when running mice could not produce adrenaline，they developed cancer at the same rate as the sedentary animals，while the sedentary animals that had been injected with extra adrenaline fought off their tumors better than other sitting mice． More remarkably，the scientists determined that adrenaline seemed to be sending biochemical signals to some of the animals'IL-6cells，making them physiologically more alert，so that when a tumor began to develop in the affected animal，those IL-6cells in turn activated the natural killer cells in the bloodstream and actually directed them to the tumors，like minute guide fish． With these results，"we show that voluntary wheel running in mice can reduce the growth of tumors，and we have identified an exercise-dependent mobilization of natural killer cells as the underlying cause of this protection，"said Pernille Hojman，a researcher at the University of Copenhagen who oversaw the new study．It perhaps provides one more incentive for us to get up and move． 58．In the first experiment，which one is the most important result the scientists found？A A．natural killer cells are much more in the bloodstreams of runners than in the sedentary mice． B．levels of interleukin-6are higher in the blood of the runners than in the sedentary mice． C．exercise such as running seemed to help the mice fight against the cancer． D．adrenaline can reduce the severity of cancer or fight it off． 59．In the follow-up experiments，the scientists foundB？ A．the hormone adrenaline has much higher levels in the blood of the exercising animals， B．how these elements in the runners-their increased adrenaline，IL-6，and natural killer immune cells fight against tumor． C．interleukin-6can both increase and decrease inflammation in the body，depending on where and how it goes to work． D．what happens inside mice at high risk for the disease． 60．According to the study，we can infer the fundamental substance to fight the cancer off isC A．adrenaline B．interleukin-6 C．natural killer cells D．genes．
18．假设你是李华，由于母亲在北京住院，所以你无法参加美国朋友约翰（John）本周六下午的生日聚会．请你给他写一封电子邮件表示歉意，内容包括： 1．表达歉意； 2．说明原因； 3．送上祝福． 注意：（1）词数100左右； （2）可以适当增加细节，以使行文连贯； （3）邮件的开头和结尾已经给出，但不计入总词数． Dear John， How is everything going with you？
2．Ecotourism Ecotourism is a responsible way to travel to natural areas which protects the environment and improves the income of the local people．For example，a walk through the rainforest is not ecotourism unless that particular walk helps the environment and the people who live there．A rafting trip （漂流旅行）is only ecotourism if it makes travelers understand the idea of protecting the area． Adventure Travel Adventure travel is an unusual experience which includes some level of risk and uncertainty，and may include some unusual means of transport．This kind of tourism is often divided into"soft"and"hard"adventure holidays．Soft adventures have a lower level of risk，have greater comfort and are less physically tiring．Hard adventures have very basic accommodation（住宿） and greater physical challenges，such as mountain climbing，backpacking or river expeditions（探险）． Sustainable（可持续的）Tourism This includes any form of tourism that does not influence the environment or stop other travelers from enjoying the same experience． Responsible Tourism Responsible tourism operates to reduce any influence by the tourists on the environment．A camping trip which aims to pick up all its rubbish leaving none behind would be considered responsible tourism． Naturebased Tourism Naturebased tourism is any holiday that concentrates on one part of nature such as a birdwatching holiday． Green Tourism Green tourism is any accommodation for a holiday which operates in an environmentally friendly way． Multisport Adventures These holidays concentrate on physical outdoor activities．Rafting，riding，mountain biking，climbing，surfing，diving，etc，may all be offered on this kind of holiday． Cultural Tourism The main point of cultural tourism is to learn from other cultures and understand more about people from different countries． 25．Which of the following is"ecotourism"？B A．A birdwatching trip which helps learn biology． B．Mountain climbing for picking up some rubbish． C．A physical outdoor activity which helps to build you up． D．A walk through the country with some paper bags to sell． 26．According to the text，which of the following is a soft adventure？D A．A usual experience of climbing． B．Biking along the country road． C．An expedition along a strange river． D．Rafting with the guide's help． 27．If you want to learn more about foreign countries，you will chooseA． A．Cultural Tourism B．Green Tourism C．Ecotourism D．Sustainable Tourism 28．This text mainly talks aboutC． A．the tips of tourism B．the advantages of tourism C．different forms of tourism D．the ways of spending holiday．
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