职称英语理工类阅读理解原文版练习(12)

　　Why Humans Walk on Two Legs 　　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 an,swer 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. 　　Tile 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. 　　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. 　　This isnt the complete answer, Soekol said.But its 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? 　　UC Davis：加州大学戴维斯分校。UC是University of California的缩写，该校有多个分校，UC Davis是其中一个。Davis以前是UC Berkeley分校的农学院，后来独立小来。Davis是一个大学城，很小的城市，Davis校园基本就构成了这个城市。 　　bipedalism：系bipedal的对应名词，这里后缀-ism表示特征、特性。 　　What did Michael Sockol and his team find out in their study of chimpanzees? 　　B The evidence why our apelike ancestors came to walk on four legs. 　　D The evidence why chimpanzees can be trained to walk on two legs. 　　A While the chimps worked in the lab ... 　　C While the chimps tried to figure out what they should do ... 　　What was the result of the finding，according to Paragraph 5? 　　B One chimp used less energy walking on two legs. 　　D All of the above. 　　A Our apelike ancestors were anatomically different but had the same gaits. 　　C Our apelike ancestors could adapt to different climate changes due to genetic variation. 　　What does fossil and molecular evidence tell us about our earliest ancestors? 　　B Due to changes in climate，they were forced to travel between food patches. 　　D They could travel longer distances on the ground than those who could use less energy.　　2． B worked out在此是运动，锻炼的意思，所以选择B。 　　B 第六段告诉了我们研究的两个假设：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；这些差异在自然选择的过程中决定了遗传变异，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战势。A、C、D都不是正确的说法，只有B在该段中被提到。