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. According to the first paragraph, artificial intelligence is()
A. the unnatural way in which robots move
B. a voiceless, box-shaped machine that performs repetitive tasks
C. a sensor that detects troubles in a robot
D. a computer program that imitates human intellectual processes
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第三篇Why Humans Walk on Two LegsA team of scientists that studied chimpanzees (黑猩猩) trained to use treadmills(跑步机) has gathered new evidence suggesting that our earliest apelike ancestors started walking on two legs because it required less energy than getting around on all fours.Michael Sockol, researcher of UC Davis, worked for two years to find an animal trainer willing to coax (劝诱) adult chimps to walk on two legs and to walk on ail fours.The five chimps also wore face masks used to help the researchers measure oxygen consumption. While the chimps worked out, the scientists collected data that allowed them to calculate which method of locomotion (移动) used less energy and why. The team gathered the same information for four adult humans walking on a treadmill.The researchers found that human walking used about 75 percent less energy and burned 75 percent fewer calories than quadrupedal and bipedal walking in chimpanzees. They also found that for some but not all of the chimps, walking on two legs was no more costly than on all fours."We were prepared to find that all of the chimps used more energy walking on two legs -but that finding wouldn’t have been as interesting," Sockol said. "What we found was much more telling. For three chimps, bipedalism was more expensive, but for the other two chimps, this wasn’t the case. One spent about the same energy walking on two legs as on all fours. The other used less energy walking upright." These two chimps had different gaits (步法) and anatomy (解剖) than their quadrupedal peers.Taken together, the findings provide support for the hypothesis that anatomical (解剖学的) differences affecting gait existed among our earliest apelike ancestors, and that these differences provided the geneticvariation which natural selection could act on when changes in the environment gave bipeds an advantage over quadrupeds.Fossil and molecular evidence suggests the earliest ancestors of the human family lived in forested areas in equatorial Africa in the late Miocene era (中世纪) some 8 to 10 million years ago, when changes in climate may have increased the distance between food patches. That would have forced our earliest ancestors to travel longer distances on the ground and favored those who could cover more ground using less energy."This isn’t the complete answer," Sockol said. "But it’s a good piece of a puzzle humans have always wondered about: How and why did we become human And why do we alone walk on two legs" The phrase "worked out" in paragraph 3 could be replaced by()
A. exercised
B. calculated
C. understood
D. planned
心房扑动的心房率是()
A. 80次/分
B. 100~150次/分
C. 150~250次/分
D. 250~350次/分
E. 350~600次/分
肠系膜动脉栓塞属:()
A. 机械性绞窄性肠梗阻
B. 机械性单纯性肠梗阻
C. 麻痹性肠梗阻
D. 血运性肠梗
E. 痉挛性肠梗阻
第三篇Why Humans Walk on Two LegsA team of scientists that studied chimpanzees (黑猩猩) trained to use treadmills(跑步机) has gathered new evidence suggesting that our earliest apelike ancestors started walking on two legs because it required less energy than getting around on all fours.Michael Sockol, researcher of UC Davis, worked for two years to find an animal trainer willing to coax (劝诱) adult chimps to walk on two legs and to walk on ail fours.The five chimps also wore face masks used to help the researchers measure oxygen consumption. While the chimps worked out, the scientists collected data that allowed them to calculate which method of locomotion (移动) used less energy and why. The team gathered the same information for four adult humans walking on a treadmill.The researchers found that human walking used about 75 percent less energy and burned 75 percent fewer calories than quadrupedal and bipedal walking in chimpanzees. They also found that for some but not all of the chimps, walking on two legs was no more costly than on all fours."We were prepared to find that all of the chimps used more energy walking on two legs -but that finding wouldn’t have been as interesting," Sockol said. "What we found was much more telling. For three chimps, bipedalism was more expensive, but for the other two chimps, this wasn’t the case. One spent about the same energy walking on two legs as on all fours. The other used less energy walking upright." These two chimps had different gaits (步法) and anatomy (解剖) than their quadrupedal peers.Taken together, the findings provide support for the hypothesis that anatomical (解剖学的) differences affecting gait existed among our earliest apelike ancestors, and that these differences provided the geneticvariation which natural selection could act on when changes in the environment gave bipeds an advantage over quadrupeds.Fossil and molecular evidence suggests the earliest ancestors of the human family lived in forested areas in equatorial Africa in the late Miocene era (中世纪) some 8 to 10 million years ago, when changes in climate may have increased the distance between food patches. That would have forced our earliest ancestors to travel longer distances on the ground and favored those who could cover more ground using less energy."This isn’t the complete answer," Sockol said. "But it’s a good piece of a puzzle humans have always wondered about: How and why did we become human And why do we alone walk on two legs" What did the researchers find in the experiment()
A. Human walking used more energy than bipedal walking in chimps
B. One chimp used about the same energy in walking on two legs as on all fours
C. Two chimps used more energy walking on two legs
D. Three chimps used less energy walking on two legs