题型：阅读理解 题类： 难易度：普通
湖北省宜荆荆随恩2023-2024学年高二下学期5月联考英语试卷
"Having the world at our fingertips" is a metaphor often used when we put our hands on information technology, like smartphones and computers. This is a good metaphor. But what is much better is how we use our hands to make things done.
Put one hand flat on a surface, palm down, and you might be able to make out the outline of 14 short bones in your thumb and fingers, in addition to 5 longer ones in your palm that are jointed to your wrist. These bones give each hand its rigid, knuckled structure. Together they're critical components of the anatomical （解剖的） architecture that allows your hand to move. At each of your fingertips there's an ever-growing, translucent plate of fibrous protein, otherwise known as a nail. Although they're nice for decoration, your nails protect and enhance your sensitivity to touch, too.
Imagine squeezing a piece of paper between your thumb and index finger, for example. We use this type of forceful pad-to-pad precision grasping without thinking about it, and literally in no time. Yet it was a breakthrough in human evolution. Other primates （灵长目动物） exhibit some kinds of precision grasps in the handling and use of objects, but not with the kind of efficiency that our hand does.
With a unique combination of traits, the human hand shaped history. No question, stone tools couldn't have become a keystone of human technology without hands that could do the job, along with a nervous （神经的） system that could regulate and coordinate the necessary signals. Even for those who have never attempted to make a spear tip or arrowhead from a rock, it's obvious that it would require strong grasps, constant rotation and repositioning, careful strikes with another hard object. And even for those who have done so, it can be a bloody business.
Of course, the most common object that people touch nowadays is a screen. And the tap-tap-tap movement of our fingers is a unique human ability, as no other primate can move their fingers as rapidly and independently as we do. Here again, we can thank the extraordinary human brain given that normal finger tapping requires the functional integrity of different parts of our central nervous system.
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