公共英語三級閲讀理解文章《肌肉和人體》

公共英語三級考試，英語閲讀理解是重點，考生在備考時，一定要留意對閲讀理解的練習。下面，小編為大家送上一篇公共英語三級閲讀理解文章，供大家參考。

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.

骨骼運動發生在人體的關節部位。這種運動是由稱為肌肉的片狀或條狀的強韌組織拖動而引起的。肌肉組織有一種特殊的收縮能力，可以帶動與之相連的骨骼。肌肉在收縮的同時，也會聚成團。肌肉以條狀或片狀形式佈滿全身，存在於皮膚與骨架之間。骨骼是身體的支架，而肌肉則構成了人的體形。大多數肌肉接兩塊骨頭，但當肌肉收縮時只有一塊骨頭運動。肌肉與不動骨相連的一端叫肌起端，與動骨相連的一端叫附着端。有些肌肉不與骨骼直接相連，而是連着附在骨骼上的不能收縮的帶狀組織或腱上。肌肉不能推動而只能拉動骨骼。要從肘部彎曲手臂，就要收縮上臂正面的.肌肉。要伸直手臂，背面的肌肉就得收縮。這兩組肌肉，正面的和背面的，稱為相反運動肌肉。當一組工作時，另一組就休息。但有時它們也一起工作。有時我們要求肌肉不僅僅做簡單的單向拖動。它們需要轉動。但只有當肌肉與骨骼形成一定角度時，它們才能轉動，從而拖動骨骼繞某個軸旋轉。有幾塊肌肉的作用較特殊，例如隔膜肌。它帶動肺部吸入空氣。呼吸基本上不是骨骼運動帶動的。

　附：公共英語三級閲讀理解是非題的四個選項有三種情況：

1.四個選項中的信息集中在一、二個句子裏。這種是非題比較容易做。只要找到相關句，細細讀一下就不難選定正確答案。

2.四個選項中的信息集中在一段裏。這樣查讀的範圍要大一些，但還是比較容易的。驗證一個，排除一個，答案就出來了。

3.四個選項中的信息分散在全文。這種是非題就比較難做，因為要化較多的時間去找各個相關句，一一去查證。一般説來，應首先把四個選項都看一遍，根據第一遍讀的印象和基本常識，儘可能先排除掉一、二個，以減少查的選項。實在排除不了，需要到文章中去一一查證的，次序也應從易到難，即從印象最深的，相關句最易找的，最容易證實的那個選項開始查。

由於時間關係，要到全文中去一一查證四個選項，效率太低。因此我們還可以首先對所有選項作一分析，根據常理，根據自己的知識結構，看看哪一選項最有可能是答案。如問哪一個true，就把四個中最可能正確的一項挑出來首先去查證;如問哪一個NOT true，就把四個中最可能是錯誤的一項挑出來首先去查證。用這一方法，最多查證兩項，答案就會出來。