Things in life start out being general cell, and they become specialized: You have tissue cells, you have muscle, brain cells. And same things happens with say, a hammer, which is general at first and becomes more specific.
生命中事物开始是一般细胞， 它们变得专业化。你有组织细胞。 你有肌肉，脑细胞。同样的道理 就如最初一般的锤子 它变得更加具体化。