代词在句子中的使用_高中英语语法_高中英语-查字典英语网

代词在句子中的使用

　　即使同一台计算机很可能已经连续完成同样的运算达数百万次之多，但每当它重复这一运算时都得准确地告诉它如何去完成这一运算。(句中有三个it,第一和第二个it都代替计算机，第三个it代替operation。might have performed是虚拟语气，表示对过去发生事情的猜测。every time是连词，引导时间状语从句。that在句中不是连词，是指示代词，作operation的定语。)

　　5.The metallurgist has recently found a metal skin for missiles and supersonic planes，one that will retain its strength at the high temperature caused by air friction.

　　冶金学家最近发明了一种用于导弹和超音速飞机的金属外壳，这种外壳在大气摩擦引起的高温下仍然能保持其强度。(one作同位语，代替skin。)

　　6.We know that air can be compressed， and it is reasonable to suppose that the air at the surface of the earth is compressed by the weight of all the air on top of it.

　　我们知道空气是可以压缩的，因而我们有理由假设：地球表面的空气受到该空气层上部所有空气重量的压缩。(第一个it是形式主语，代替不定式短语to suppose...。句末的it是人称代词，代替“地球表面上的空气。)

　　7.It follows from the principle of relativity that Newton’s second law of motion，although fundamental in classical mechanics，only has an approximate and by no means complete validity.