GWD31 Q20-Q23 （即 GWD TN21 Q20-23）

小妖藏尼

GWD31 Q20-Q23 （即 GWD TN21 Q20-23）

哪位NN能帮忙解释一下这几道阅读题怎么解吗？应该定位在哪里啊...

Anthropologists once thought that the ancestors of modern humans began to walk upright because it freed their hands to use stone tools, which they had begun to make as the species evolved a brain of increased size and mental capacity. But discoveries of the three-million-year-old fossilized remains of our hominid ancestor Australopithecus have yielded substantial anatomical evidence that upright walking appeared prior to the dramatic enlargement of the brain and the development of stone tools.
     Walking on two legs in an upright posture (bipedal locomotion) is a less efficient proposition than walking on all fours (quadrupedal locomotion) because several muscle groups that the quadruped uses for propulsion must instead to provide the biped with stability and control. The shape and configuration of various bones must likewise be modified to allow the muscles to perform these functions in upright walking. Reconstruction of the pelvis (hipbones) and femur (thighbone) of “Lucy”, a three-million-year-old skeleton that is the most complete fossilized skeleton from the australopithecine era, has shown that they are much more like the corresponding bones of the modern human than like those of the most closely related living primate, the quadrupedal chimpanzee. Lucy’s wide, shallow pelvis is actually better suited to bipedal walking than is the rounder, bowl-like pelvis of the modern human, which evolved to form the larger birth canal needed to accommodate the head of a large-brained human infant. By contrast, the head of Lucy’s baby could have been no larger than that of a baby chimpanzee.
   If the small-brained australopithecines were not toolmakers, what evolutionary advantage did they gain by walking upright? One theory is that bipedality evolved in conjunction with the nuclear family: monogamous parents cooperating to care for their offspring. Walking upright permitted the father to use his hands to gather food and carry it to his mate from a distance, allowing the mother to devote more time and energy to nurturing and protecting their children. According to this view, the transition to bipedal walking may have occurred as long as ten million years ago, at the time of the earliest hominids, making it a crucial initiating event in human evolution.


20: The passage suggests that proponents of the theory mentioned in lines 50-54 (One theory is … offspring) assume that which of the following steps in human evolution occurred most recently? （答案：C）
A. development of a nuclear family structure
B. transition from walking on all fours to walking upright
C. dramatic enlargement of the brain
D. use of the hands to gather and carry food
E. modification of propulsive muscles to provide stability and control in locomotion
为什么选C 定位在哪里？题干是问什么？很晕

yvonnemirror

题干是在问：这个theory假设下面那个步骤是最近发生的？（最近发生的是指最后发生的）

20: The passage suggests that proponents of the theory mentioned in lines 50-54 (One theory is … offspring) assume that which of the following steps in human evolution occurred most recently?
A.    development of a nuclear family structure（这个选项可以从最后一段得到发生在直立行走的同时，也就是脑子进化之前）
B.    transition from walking on all fours to walking upright（这个就是直立行走，也是发生在脑子进化之前）
C.    dramatic enlargement of the brain（脑子进化）
D.    use of the hands to gather and carry food
（这个发生在直立行走的同时，定位在最后一段Walking upright permitted the father to use his hands to gather food and carry it to his mate from a distance，也就是你这儿倒数第三行）
E.    modification of propulsive muscles to provide stability and control in locomotion（这个其实也就是直立行走的过程中发生的，定位在第二段）

如果你不知道为什么直立行走发生在脑子进化之后。解释：文章从第一段开始的主题句，也就是最后一句话后半截
upright walking appeared prior to the dramatic enlargement of the brain and the development of stone tools.
其中说了
直立行走是发生在脑子进化和使用工具之前的！
最后一段也有说明。

如果你还是不太懂。这篇文章我有按小安阅读分析过，可以发给你。。。