Questions 19 to 21 are based on the recording you have just heard.
问题1选项
A.It consumes almost a quarter of the body’s total energy.
B.It continues to burn up calories to help us stay in shape.
C.It uses up much less energy than it does in deep thinking.
D.It remains inactive without burning calories noticeably.
问题2选项
A.Energy usage devoted to active learning accounts for a big part of it.
B.Much of the consumption has nothing to do with conscious activities.
C.A significant amount of it is for performing difficult cognitive tasks.
D.It has something to do with the difficulty of the activities in question.
问题3选项
A.It is conducive to relieving mental exhaustion.
B.It is a prerequisite for any mental activity.
C.It is believed to remain basically constant.
D.It is thought to be related to food consumption.
Recording Two In 1994, the World Chess Championship was called off abruptly, due to the withered frame of a player who is competing for the title. He wasn’t alone in experiencing the extreme physical effects of the game. Elite players can reportedly burn up to an absurd 6,000 calories in one day. Does that mean that thinking harder is a simple route to losing weight? Well, [19] when the body is at rest，we know that the brain uses up a startling 20% to 25% of the body’s overall energy. This level of utilization actually makes the brain the most energy-expensive organ in the body, and yet it makes up only 2% of the body’s weight overall. So the more we put this organ to work, the more calories we’ll burn? Technically, the answer is yes, for cognitively difficult tasks. What counts as a “difficult” mental task varies between individuals. But generally, it could be described as something that the brain cannot solve easily using previously learned routines, or tasks that change the conditions continuously. However, deep thinking will not burn off the calories gained from eating a sugary snack. Because in relation to the brain’s huge overall energy usage, which is devoted to a multitude of tasks, the energy required just to think harder is actually comparatively tiny. [20] We’re unconscious of most of what uses up the brain’s energy. A lot of that activity is unrelated to conscious activities like learning how to sing or play the guitar. The brain is able to allocate blood (and thus energy) to particular regions that are being active at that point. But [21] the overall energy availability in the brain is thought to be constant. So, while there might be significant increases in energy use at localized regions of the brain when we perform difficult cognitive tasks, when it comes to the whole brain’s energy budget overall, these activities don’t significantly alter it. So, why did the chess champion grow too skinny to compete in his chess competition? The general consensus is that it mostly comes down to stress and reduced food consumption, not mental exhaustion. Keeping your body pumped up for action for long periods of time is very energy-demanding. If you can’t eat as often or as much as you can or would normally—then you might lose weight.
19. What do we learn about the brain when the body is at rest? 【试题答案】A 【试题解析】题目问的是当身体处于静止状态时大脑的情况。说话者提及，当身体处于静止状态时，大脑会消耗身体总能量的20%到25%，A选项“它消耗的能量几乎占人体总能量的四分之一”是对原文录音的同义转换，因此正确。B选项“它继续燃烧卡路里，帮助我们保持体形”和C选项“它比在深度思考时消耗的能量更少”在录音中均没有信息提及，因此排除；D选项“它保持不活跃，没有明显燃烧卡路里”与录音表达恰好相反，因此不正确。 20. What does the speaker say about the consumption of the brain’s energy? 【试题答案】B 【试题解析】题目问说话者对大脑能量的消耗有什么看法？说话者提出，我们无从感觉到是什么消耗了大脑的能量，而这些消耗能量的活动大部分与有意识的活动无关，因此B选项“大部分消耗与有意识的活动无关”正确。A选项“用于主动学习的能量消耗占了很大一部分”在录音中并未提及；C选项“有相当一部分是用于执行困难的认知任务”和D选项“这与正在论及的活动的难度有关”。录音原文表述的是：当我们执行困难的认知任务时，大脑局部区域的能量使用可能会显著增加，但当涉及大脑的整体能量预算时，这些活动并不会使它有显著改变。C选项和D选项与原文表述不符，因此排除。 21. What do we learn about the overall energy availability in the brain? 【试题答案】C 【试题解析】题目问我们了解到大脑中的整体能量供应是怎样的？录音中提到大脑中的总体能量供应是恒定的。因此C选项“人们认为它基本保持不变”正确。A选项“它有利于缓解精神疲惫”；B选项“它是任何心理活动的前提”以及D选项“它被认为与食物消耗有关”在录音中均没有信息提及，因此可排除。
