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公共英语三级阅读理解文章《肌肉和人体》
公共英语三级考试，英语阅读理解是重点，考生在备考时，一定要留意对阅读理解的练习。下面，小编为大家送上一篇公共英语三级阅读理解文章，供大家参考。
Body It is in the joints of the human body that movements of the bones take place. The movement itself is caused by the pull of sheets and cords of very tough tissue called muscle. Muscle tissue has the special ability to shorten itself so that the bone on which it pulls has to move. When muscle tissue shortens, it also bunches up. Muscle tissue covers the body in sheets and bands that lie between the skin and the skeleton. The bones are the framework of the body, but the muscles fill out the body shape. Most muscles extend from one bone to another. When the muscle between the bones shortens, one bone has to move. The point where the muscle is fastened to the unmoving bone is called the origin of the muscle, whereas the point where the muscle is not fastened to the bone that is to be moved is called the insertion. Sometimes the muscle is not attached directly to the bone but to a tough, nonstretchable cord, or tendon, that is attached to the bone. Muscles do not push; they can only pull. To bend the arm at the elbow, the muscle at the front of the upper arm has to shorten and bunch up. To unbend the arm other muscles in the back of the arm have to shorten. These two sets of muscles - the front and the back - are said to act in opposition to each other. When one set is working, the other set is usually relaxed. But there are times when both of them work. Sometimes muscles are called upon to do more than simply pull in one direction. They may have to perform a turning motion. To be able to do this, the muscle must be attached to the bone at an angle. By pulling, the muscle can cause the bone to pivot. A few muscles have special functions. The diaphragm, for example, forces the lungs to take in air. This part of breathing is not primarily a bone moving operation.
骨骼运动发生在人体的关节部位。这种运动是由称为肌肉的片状或条状的强韧组织拖动而引起的。肌肉组织有一种特殊的收缩能力，可以带动与之相连的骨骼。肌肉在收缩的同时，也会聚成团。肌肉以条状或片状形式布满全身，存在于皮肤与骨架之间。骨骼是身体的支架，而肌肉则构成了人的体形。大多数肌肉接两块骨头，但当肌肉收缩时只有一块骨头运动。肌肉与不动骨相连的一端叫肌起端，与动骨相连的一端叫附着端。有些肌肉不与骨骼直接相连，而是连着附在骨骼上的不能收缩的带状组织或腱上。肌肉不能推动而只能拉动骨骼。要从肘部弯曲手臂，就要收缩上臂正面的肌肉。要伸直手臂，背面的肌肉就得收缩。这两组肌肉，正面的和背面的，称为相反运动肌肉。当一组工作时，另一组就休息。但有时它们也一起工作。有时我们要求肌肉不仅仅做简单的单向拖动。它们需要转动。但只有当肌肉与骨骼形成一定角度时，它们才能转动，从而拖动骨骼绕某个轴旋转。有几块肌肉的作用较特殊，例如隔膜肌。它带动肺部吸入空气。呼吸基本上不是骨骼运动带动的。
附：公共英语三级阅读理解是非题的四个选项有三种情况：
1.四个选项中的信息集中在一、二个句子里。这种是非题比较容易做。只要找到相关句，细细读一下就不难选定正确答案。
2.四个选项中的信息集中在一段里。这样查读的范围要大一些，但还是比较容易的。验证一个，排除一个，答案就出来了。
3.四个选项中的信息分散在全文。这种是非题就比较难做，因为要化较多的时间去找各个相关句，一一去查证。一般说来，应首先把四个选项都看一遍，根据第一遍读的印象和基本常识，尽可能先排除掉一、二个，以减少查的选项。实在排除不了，需要到文章中去一一查证的，次序也应从易到难，即从印象最深的，相关句最易找的，最容易证实的那个选项开始查。
由于时间关系，要到全文中去一一查证四个选项，效率太低。因此我们还可以首先对所有选项作一分析，根据常理，根据自己的知识结构，看看哪一选项最有可能是答案。如问哪一个true，就把四个中最可能正确的一项挑出来首先去查证;如问哪一个NOT true，就把四个中最可能是错误的一项挑出来首先去查证。用这一方法，最多查证两项，答案就会出来。
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