The researchers found that human walking used about 75 percent less energy and burned 75 percent fewer calories than quadrupedal and bipedal2 walking in chimpanzees. They also found that for some but not all of the chimps, walking on two legs was no more costly than knucklewalking. “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.(第5段答案相关句) For three chimps, bipedalism3 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 four. The other used less energy walking upright.” These two chimps had different gaits and anatomy than their knucklewalking peers. (可能的考点设置句)(第6段)Taken(拿， 拿走, 占领, 获得) together(一起), the findings(研究发现) provide support for (为...提供了支持)the hypothesis (假设)that anatomical (解剖学上的)differences(差异)affecting gait existed among(在...之中) our earliest apelike ancestors(与A不一致), and that these differences(差异) provided(提供) the genetic variation(遗传变异) which natural selection (自然选择)could act on(对...起作用)when changes in the environment(环境) gave bipeds(两足动物) an advantage over(优于...的优势) quadrupeds(四足动物)(该部分内容与选项D结构和用词一致， 因此D是答案). 第六段告诉了我们研究的两个假设：一种假设：猿人祖先在解剖学意义上存在着差异，这一差异影响了它们的步态;另一种假设：这些差异为自然选择所决定的遗传变异提供了可能性，而环境变化使得两足行走的猿人比起四足行走的猿人更有优势。因此B是答案。 5. What does fossil(化石的， 化石) and molecular(分子) evidence(证据) tell us about our earliest(初期的， 早期的) ancestors(祖先)? A) They experienced(经历) more climate changes than we do today. B) Due to(因为) changes in climate, they were forced to (被迫)travel(旅行) between food patches(片，碎片， 小块地). C) They could cover(通过，覆盖， 包括) more ground (地面， 土地)than their quadrupedal (四足的)peers(同等的人) because they used less energy. D)They could travel longer distances(距离) on the ground (在地面上)than those who could use less energy(能量). 5.C. 利用问题句及被选项中的细节信息结构(字体加粗文字)共同作为答案线索， 在文章中查找答案相关句 A team of scientists that studied chimpanzees trained to use treadmills 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. “When our earliest ancestors started walking on two legs, they took the first steps toward becoming human,” said lead researcher Michael Sockol of UC Davis1. “Our findings help answer why.” Sockol worked for two years to find an animal trainer willing to coax adult chimps to walk on two legs and to “knucklewalk” on all fours on the sort of treadmill found in most gyms. The five chimps also wore face masks used to help the researchers measure oxygen consumption. While the chimps worked out, the scientists collected metabolic and other data that allowed them to calculate which method of locomotion 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 bipedal2 walking in chimpanzees. They also found that for some but not all of the chimps, walking on two legs was no more costly than knucklewalking. “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, bipedalism3 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 four. The other used less energy walking upright.” These two chimps had different gaits and anatomy than their knucklewalking peers. (第4题答案相关句)Taken together, the findings provide support for the hypothesis that anatomical differences affecting gait existed among our earliest apelike ancestors, and that these differences provided the genetic variation which natural selection could act on when changes in the environment gave bipeds an advantage over quadrupeds. Fossil(化石的) and molecular (分子的)evidence(证据) suggests(显示) the earliest ancestors(祖先) of the human family lived in forested(被森林所覆盖的) areas in equatorial(近赤道的) Africa(非洲) in the late(迟的，末期的) Miocene era (中世纪末期)some(大约) 8 to 10 million years ago(以前), when changes in climate may have increased the distance between food patches. That would have forced(强迫) our earliest ancestors(早期的祖先)(问题句中的核心结构) to travel longer distances(距离) on the ground and favored(赞成， 帮助， 有利于) those who could cover(通过) more ground using less energy. (C中的cover more ground的近义结构travel longer distance , less energy都出现这个句子中，因此可能C是答案)。 “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?” 倒数第二段提供了问题的答案。travel longer distances用的是比较级，这里是将两足行走的猿人与上文中四足行走的猿人做比较。those who could cover more ground using less energy指的是上文提到的与四足行走的猿人相比，体能消耗较小的两足行走猿人。其他选择都不是正确说法。 |
