【T17】
A.ORIGIN
B.COMMUNICATE WITH
C.WRITTEN DOWN
D.LEARN A.THE MORE WE READ AND【T13】_______
B.WHICH COULD BE【T14】______
C.THE【T15】______OF LANGUAGE IS A MYSTERY
D.THEY COULD【T16】______EACH OTHER HOW MEN FIRST LEARNT TO INVENT WORDS IS UNKNOWN; IN OTHER WORDS,【T17】______.ALL WE REALLY KNOW IS THAT MEN, UNLIKE ANIMALS, SOMEHOW INVENTED CERTAIN SOUND TO EXPRESS THOUGHTS AND FEELINGS, ACTIONS AND THINGS, SO THAT 【T18】______; AND THAT LATERTHEY AGREED UPON CERTAIN SIGNS, CALLED LETTERS, WHICH COULD BE COMBINED TO REPRESENT THOSESOUNDS, AND【T19】______.THOSE SOUNDS, WHETHER SPOKEN OR WRITTEN IN LETTERS, WE CALLWORDS.THE POWER OF WORDS, THEN, LIES IN THEIR ASSOCIATIONS—THE THINGS THEY BRING UP BEFORE OUR MINDS.WORDS BECOME FILLED WITH MEANING FOR US BY EXPERIENCE; AND THE LONGER WE LIVE, THE MORE CERTAIN WORDS RECALL TO US THE GLAD AND SAD EVENTS OF OUR PAST; AND【T20】______, THE MORE THE NUMBER OF WORDS THAT MEAN SOMETHING TO US.
正确答案：C
根据空格前的“inotherwords”可知空格处内容是“inotherwords”前内容“人类最开始时是如何学会创造词语的尚未可知”的同义转换所以选C
