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第二篇Real-World RobotsWhen you think of a robot, do you imagine a shiny, metallic device having the same general shape as a human being, performing humanlike functions, and responding to your questions in a monotone (单调的) voice accentuated (强调) by high-pitched tones and beeps This is the way many of us imagine a robot, but in the real world a robot is not humanoid at all. Instead a robot often is a voiceless, box-shaped machine that efficiently carries out repetitive or dangerous functions usually performed by humans. Today’s robot is more than an automatic machine that performs one task again and again. A modern robot is programmed with varying degrees of artificial intelligence, that is, a robot contains a computer program that tells it how to perform tasks associated With human intelligence, such as reasoning, drawing conclusions, and learning from past experience.A robot does not possess a human shape for the simple reason that a two-legged robot has great difficulty remaining balanced. A robot does, however, move from place to place on wheels and axles (轮轴) that roll and rotate. A robot even has limbs that turn round and move in combination with joints and motors. To find its way in its surroundings, a robot utilizes various built-in sensors. Antennae attached to the robot’s base detect anything they bump into. If the robot starts to shake as it moves on an incline, a gyroscope (陀螺仪) inside it senses the vertical differential. To determine its distance from an object and how quickly it will reach the object, the robot bounces beams of laser light and ultrasonic sound waves off obstructions (障碍物) in its path. These and other sensors constantly feed information to the computer, which then analyzes the information and corrects or adjusts the robot’s actions. As science and technology advance, the robot too will progress in its functions and use of artificial intelligence programs. The last paragraph suggests that future robots will（）
Debate over the Use of Renewable EnergyAusubel of Rockefeller University in New York, US says the key renewable (可再生的) energy sources, including sun, wind and biofuels, would all require vast amounts of land if developed up to large scale production - unlike nuclear power. That land would be far better (51) alone, he says. Renewables look (52) when they are quite small. But if we start producing renewable energy on a large (53) , the fallout (结果) is going to be horrible.Ausubel draws his conclusions by analysing the amount of energy that renewables, natural gas and nuclei (原子核) can (54) in terms of power per square metre of land used. Moreover, he claims that (55) renewable energy use increases, this measure of efficiency will decrease as the best land for wind, biofuels, and solar power gets used up.Solar power is much more (56) than biofuel in terms of the area of land used, but it would still (57) 150 square kilometres of photovoltaic (光电的) cells to match the energy production of the 1000 MW nuclear plant. In another example, he says (58) the 2005 US electricity demand via wind power alone would need 780,000 square kilometres, an area the (59) of Texas.However, several experts are highly critical of Ausubel’s (60) . John Turner of the US government’s National Renewable Energy Laboratory says that even if the US got all of its (61) from solar energy, it would still need less than half the amount of land that has been paved over (62) highways. Further, it need not (63) up additional land. The US could get a quarter of its energy just from covering rooftops of existing buildings, he says.According to Turner, the same "dual use" also (64) to wind power. "The footprint for wind is only 5% of the land that it (65) . Farmers can still farm the land that the turbines are on." Turner says looking solely at land use is an oversimplification of the issue. 56（）
Debate over the Use of Renewable EnergyAusubel of Rockefeller University in New York, US says the key renewable (可再生的) energy sources, including sun, wind and biofuels, would all require vast amounts of land if developed up to large scale production - unlike nuclear power. That land would be far better (51) alone, he says. Renewables look (52) when they are quite small. But if we start producing renewable energy on a large (53) , the fallout (结果) is going to be horrible.Ausubel draws his conclusions by analysing the amount of energy that renewables, natural gas and nuclei (原子核) can (54) in terms of power per square metre of land used. Moreover, he claims that (55) renewable energy use increases, this measure of efficiency will decrease as the best land for wind, biofuels, and solar power gets used up.Solar power is much more (56) than biofuel in terms of the area of land used, but it would still (57) 150 square kilometres of photovoltaic (光电的) cells to match the energy production of the 1000 MW nuclear plant. In another example, he says (58) the 2005 US electricity demand via wind power alone would need 780,000 square kilometres, an area the (59) of Texas.However, several experts are highly critical of Ausubel’s (60) . John Turner of the US government’s National Renewable Energy Laboratory says that even if the US got all of its (61) from solar energy, it would still need less than half the amount of land that has been paved over (62) highways. Further, it need not (63) up additional land. The US could get a quarter of its energy just from covering rooftops of existing buildings, he says.According to Turner, the same "dual use" also (64) to wind power. "The footprint for wind is only 5% of the land that it (65) . Farmers can still farm the land that the turbines are on." Turner says looking solely at land use is an oversimplification of the issue. 52（）
（一） 某水坝工程可以满足各种功能要求的方案有A和B两个：A方案的建造费用为1000万元，每年的运行及维护费用为l50万元；B方案的建造费用为l500万元，每年的运行及维护费用为l00万元。两个方案的寿命期皆可以看作为无限年。设贷款的利率为5％。 根据题意，回答下述问题： B方案总费用的现值为（ ）万元。
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