题目

Studies show that older people tend to remember the positive things in life rather than the negative things, while younger people remember the positive and negative equally well. The dominant psychological theory to explain this is that older people are aware of their limited time left, so they prioritize positive emotional experiences. But about a decade ago, I worked with biologist Robert Trivers on his idea that there was an evolutionary basis for older people’s increased positive outlook. Our research took us in the fascinating direction of exploring how the body uses its energy.When our ancestors needed more energy than usual, perhaps while being chased by a tiger, they had to get that energy from somewhere in the body. Could they borrow it from the brain? That organ uses 20 percent of our metabolic (新陈代谢) output, whether we are solving math problems or watching television reruns. Due to this constant energy requirement, borrowing energy from the brain when our need surpasses the available supply is not an option. Perhaps we could borrow energy from our muscles. Because we use far more muscle energy when we are active than when at rest, in principle, we could borrow energy when we are sitting. But the problem is that most of the energy-demanding emergencies of our ancestors required a muscular response. There was no way to borrow energy from our muscles during an emergency because relaxing when a tiger showed up was not an effective response. This brings us to our immune system, which, when strong, protects us from many illnesses and diseases. Like the brain, the immune system works at great metabolic cost, but largely in the service of keeping us healthy in the future. We have an enormous number of immune cells coursing through our body, a momentary break from production is fine. So, when our body needs extra energy, one of the places it goes is our immune function. When you’re being chased by a tiger, you don’t need to waste energy making immune cells to fight off tomorrow’s cold. What you need is to shift all available energy resources to your legs, with the hope that you will live to experience another cough or sneeze.As a result, our immune system evolved to run in maximum amounts when we’re happy, but to slow down dramatically when we’re not. With this background in mind, Trivers supposed that older people evolved a strategy of turning this relationship on its head, becoming more focused on the positive things in life in an effort to enhance their immune functioning. This was helped along by their knowing much more about the world than younger adults, so they can deal with some of the unpleasant things in life more easily.【1】According to Robert Trivers, when our body needs extra energy, ______.A. muscles will respond to it by relaxing a little bitB. organs will speed up metabolic processes to answer itC. immune system will temporarily shut down to fulfill itD. brain will satisfy it by sharing optional metabolic output【2】In paragraph 3 “this relationship” most probably refers to the one between ______.A. experiences and related knowledge B. happiness and biological evolutionC. immune function and health D. optimism and length of life【3】What can be concluded from Robert Trivers’ study?A. Younger people adopt strategies of handling tense situations from everyday life.B. Our ancestors evolved their immune systems in fighting against fierce animals.C. Realizing that their days are numbered, older people prefer being positive.D. Being negative drains energy from our body, lowering resistance to disease.【4】Which of the following is the best title of the passage?A. Brain, muscles and immune system B. Age, health and happinessC. Ancestors, emergency and evolution D. Energy, effort and response 答案：【答案】【1】C【2】D【3】D【4】B【解析】这是一篇说明文。研究表明，老年人往往会记住生活中积极的事物，而不是消极的事物。十年前作者与生物学家罗伯特·特里弗斯合作研究身体是如何使用能量的，他们的发现解释了这一现象。【1】推理判断题。根据We have an enormous number of immune cells coursing through our body, a momentary break from production is fine. So, when our body needs extra energy, one of the places it goes is our immune function.可知我们的身体里有大量的免疫细胞，暂时停止运作是可以的。因此，当我们的身体需要额外的能量时，（我们的身体）会去找免疫系统。由此可以推断，免疫系统会暂时停止来为身体提供额外的能量。选C。【2】推理判断题。根据后文 “becoming more focused on the positive things in life in an effort to enhance their immune functioning.” 可知老人们更加关注生活中积极的事物，是为了增强他们的免疫功能。也就是说积极与免疫功能之间有关系，越积极，免疫功能越强，就能活得越久，所有选项中D项（乐观与寿命）之间最切题，故选D。【3】推理判断题。根据“As a result, our immune system evolved to run in maximum amounts when we’re happy, but to slow down dramatically when we’re not.”可知当我们快乐时，我们的免疫系统进化到最大程度，但是当我们不快乐时，免疫系统会减弱。由此推断，消极会消耗我们身体的能量，降低对疾病的抵抗力。选D。【4】主旨大意题。作者开头提出老年人更关注积极的事情，后文提到积极的情绪会增强免疫系统，所以本文主要讲的是年龄，健康与积极的情绪之间的关系，选B。

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