It is predicted that there will be four scientific breakthroughs in the 21st century. We’ll know where we came from. Why doe

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问题     It is predicted that there will be four scientific breakthroughs in the 21st century.
    We’ll know where we came from. Why does the universe exist? To put it another way, why is there something instead of nothing? Since the 1920s, scientists have known the universe is expanding, which means it must have started at a definite time in the past. They even have developed theories that give a detailed picture of the evolution of the universe from the time it was a fraction of a second old to the present. Over the next couple of decades, these theories will be refined by data from extraordinary powerful new telescope.
    We’ll crack the genetic code and conquer cancer. In 19th century operas, when the heroine coughs in the first act, the audience knows she will die of tuberculosis in Act 3. But thanks to 20th-century antibiotics, the once-dreaded, once-incurable disease now can mean nothing more serious than taking some pills. As scientists learn more about the genetic code and the way cells work at the molecular level, many serious diseases—cancer, for one—will become less threatening. Using manufactured "therapeutic" viruses, doctors will be able to replace cancer-causing damaged DNA with healthy genes, probably administered by a pill or injection.
    We’ll live longer(120 years?). If the normal aging process is basically a furious, invisible contest in our cells—a contest between damage to our DNA and our cells’ ability to repair that damage—then 21st-century strides in genetic medicine may let us control and even reverse the process. But before we push scientists to do more, consider: Do we really want to live in a world where no one grows old and few children are born because the planet can hold only so many people? Where would new ideas come from? What would we do with all that extra time?
    We’ll have a brain road map. This is the real final frontier of the 21st century: The brain is the most complex system we know. It contains about 100 billion neurons, each connected to as many as 1,000 others. In the 21st century, we will use advanced forms of magnetic resonance imaging to produce detailed maps of the neurons in operation. We’ll be able to say with certainty which ones are working when you read a word, when you say a word, when you think about a word, and so on.
According to the passage, the aging process is a struggle between

选项 A、destruction and repair.
B、damage and control.
C、control and reverse.
D、repair and reverse.

答案A

解析 根据本文内容,衰老过程是______之间的斗争?[A]破坏和修复。[B]损害和控制。[C]控制和逆转。[D]修复和逆转。根据题目中的关键词aging process可以把相关信息定位到第四段的:If the normalaging process is…contest in our cells—a contest between damage to our DNAand our cells’ability to repair that damage——then 21st—century strides… 其中破折号的部分是同位语,在考试中,我们可以先不看破折号里的内容,而先看懂句子主干,即:如果说通常的衰老过程主要是我们细胞内的一场激烈而不可见的竞赛的话,那么21世纪遗传医学的巨大成就会使我们能够控制、甚至逆转这一过程。然后再分析附加成分,即:一场对我们的脱氧核糖核酸进行破坏同我们体内的细胞对被破坏的组织进行修复的竞赛。由此,便可直接选出正确答案[A]。
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