The evolution of speech may have been the most important factor of all．When early man ed the loom (工具) of language, his progress accelerated dramatically．Through the spoken word a new invention in tool-malting, for example, could be communicated to everyone; in this way the innovativeness of the individual enhanced the survival prospects of his fellows, and the creative strength of one became the strength of all．More important, through language the ideas of one generation could be passed on to the next, so that each generation inherited not only the genes of its ancestors but also their collective wisdom, transmitted through the magic of speech．A million years ago, when this magic was not yet perfected and language was a cruder art, those bands of men who possessed the new gift in the highest degree were strongly favored in the struggle for existence．But the fabric of speech is woven out of many threads．The physical attributes of a voice bow, lips, an tongue were among the necessary traits; but a good brain was also essential, to frame．an abstract thought or represent an object by a word.
Now the law of the survival of the fittest began to work on the population of early men, Steadily, the physical apparatus for speech improved．At the same time, the center of the brain devoted to speech grew in size and complexity, and in the course of many generations the whole brain grew with them．Once more, as with the use of tools, reciprocal forces came into play in which speech stimulated better brains, and brains improve the art of speech, and the curve of brain growth spiraled upward.
Which factor played the most important role in the evolution of human intelce? Was it the most pressure of the Ice-Age climate? Or tools? Or language? No one can tell; all worked together, through Darwin's law of natural selection, to produce the dramatic increase in the size of the brain that has been recorded in the fossil record in the last million years．The brain reached its present size about one hundred thousand years ago, and its growth ceased．Man's body had been shaped into its modern form．several hundred thousand years before that．Now brain and body were complete．Together they made a new and marvelous creature, charged with power, intelce, and creative energy．His wits had been honed (磨砺) by the fight against hunger, cold, and the natural enemy; his form．had been molded in the crucible of adversity．In the annals of anthropology his arrival is celebrated by a change in name, from Homo erectus--the Man who stands erect--to Homo sapiens--the Man of wisdom.
What can be preceded according to the passage?

The evolution of speech may have been the most important factor of all. When early man ed the loom (工具) of language, his progress accelerated dramatically. Through the spoken word a new invention in tool-malting, for example, could be communicated to everyone; in this way the innovativeness of the individual enhanced the survival prospects of his fellows, and the creative strength of one became the strength of all. More important, through language the ideas of one generation could be passed on to the next, so that each generation inherited not only the genes of its ancestors but also their collective wisdom, transmitted through the magic of speech. A million years ago, when this magic was not yet perfected and language was a cruder art, those bands of men who possessed the new gift in the highest degree were strongly favored in the struggle for existence. But the fabric of speech is woven out of many threads. The physical attributes of a voice bow, lips, an tongue were among the necessary traits; but a good brain was also essential, to frame. an abstract thought or represent an object by a word.
Now the law of the survival of the fittest began to work on the population of early men, Steadily, the physical apparatus for speech improved. At the same time, the center of the brain devoted to speech grew in size and complexity, and in the course of many generations the whole brain grew with them. Once more, as with the use of tools, reciprocal forces came into play in which speech stimulated better brains, and brains improve the art of speech, and the curve of brain growth spiraled upward.
Which factor played the most important role in the evolution of human intelce? Was it the most pressure of the Ice-Age climate? Or tools? Or language? No one can tell; all worked together, through Darwin's law of natural selection, to produce the dramatic increase in the size of the brain that has been recorded in the fossil record in the last million years. The brain reached its present size about one hundred thousand years ago, and its growth ceased. Man's body had been shaped into its modern form. several hundred thousand years before that. Now brain and body were complete. Together they made a new and marvelous creature, charged with power, intelce, and creative energy. His wits had been honed (磨砺) by the fight against hunger, cold, and the natural enemy; his form. had been molded in the crucible of adversity. In the annals of anthropology his arrival is celebrated by a change in name, from Homo erectus--the Man who stands erect--to Homo sapiens--the Man of wisdom.
What can be preceded according to the passage?