题目内容
5.A hundred years ago on Monday,a once-mighty species became extinct.At the Cincinnati Zoo,a passenger pigeon named Martha died at the age of 29.It was a quiet end to a noisy species.As recently as the mid-1800s,billions of passenger pigeons swarmed across the eastern half of the United States.But they proved no match for humans,whose rapidly advancing technology drove the birds to extinction in a matter of decades.Other species were also spiraling toward extinction in the late 1800s,but the destruction of the passenger pigeon happened on full public display."It became the icon (标志) of extinction."
A hundred years later,the passenger pigeon remains iconic.In 2012,a group of scientists launched a project now named the Great Passenger Pigeon Comeback to create cloned passenger pigeons-or at least birds genetically engineered to have passenger pigeon features.Two years later,project scientists are still hard at work.But they can't say when-or even if-the bird will fly again.
Nor has anyone ever cloned a bird,so every step in the plan will take the project scientists into unknown scientific territory to give rise to a passenger pigeon.Extracting an undamaged passenger pigeon gene from museum specimens (样本) seems impossible.Novak and his colleagues are hoping to reconstruct the gene of the band-tailed pigeons,the closest living relatives of passenger pigeons,which live in the western United States.
Even if the scientists end up with some passenger pigeon chicks in a few years,they will still be a long way from successfully reestablishing the species.However,people today can learn many lessons in its disappearance and apply it to protecting threatened species today
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28.The underlined word"spiraling"in the second paragraph meansB.
A.circling at a lower speed
B.declining sharply
B.marching forward fast
D.increasing gradually
29.The project Great Passenger Pigeon Comeback is intended toD.
A,reintroduce passenger pigeons to America
B.experiment with cloning technology
C.protect the endangered band-tailed pigeons
D.recreate an extinct bird species
30.Which of the following are the difficulties of carrying out the project?C
a.They couldn't find an undamaged gene of the species.
b.Cloning a bird is a completely new thing.
c.The museum refused to provide the sample of the bird.
d.They can't get the closest relative of the passenger pigeon.
e.There is no previous experience to rely on.
A.a,b,c
B.b,c,d
C.a,b,e
D.c,d,e
31.What does the author think of the efforts the scientists are making?A
A.It is well worth having such a try.
B.They can hardly achieve their goal.
C.They are only steps away from success.
D.It is meaningless for the species protection.
分析 本文主要讲述了一百年前因为科技的迅速发展,导致了旅鸽和其他物种的灭绝,现在科学家们正在研究如何克隆已经灭绝的旅鸽.由于以前从来没有克隆鸟类的先例,所以这是一个全新的实验,没有任何经验可以借鉴,因此克隆的这条路还很长.然而今天的人们可以从中得到教训,并把它应用于保护濒危物种.
解答 28.B 词义猜测题.根据第二段But they proved no match for humans,whose rapidly advancing technology drove the birds to extinction in a matter of decades.可知迅速发展的技术使鸟类濒临灭亡.而这个词前面的"also"表明其它物种也是如此,所以这个词的意思是"数量骤减",故选B.
29.D 细节理解题.根据第三段In 2012,a group of scientists launched a project now named the Great Passenger Pigeon Comeback to create cloned passenger pigeons-or at least birds genetically engineered to have passenger pigeon features.可知他们的目的是为了克隆已经灭绝的旅鸽,故选D.
30.C 细节理解题.根据第四段Nor has anyone ever cloned a bird,so every step in the plan will take the project scientists into unknown scientific territory to give rise to a passenger pigeon.Extracting an undamaged passenger pigeon gene from museum specimens (样本) seems impossible.可知以前从来没有克隆鸟类的先例,所以这是一个全新的实验,没有任何经验可以借鉴,而且他们也无法从博物馆的样本中提取完整的基因,故选C.
31.A 推理判断题.根据最后一段However,people today can learn many lessons in its disappearance and apply it to protecting threatened species today.可知人们可以从旅鸽的灭绝中得到教训,并把它应用于保护濒危物种,所以这个实验是值得的,故选A.
点评 本文考察学生的理解推断能力以及细心程度,只要抓住文章的关键词,采用寻读的方法查找细节,就能找到正确答案.
A. | failed | B. | abandoned | C. | ignored | D. | betrayed |