美国的零售商行业，在这十年来，发生了前所未有的变化。
Retailers in the us have seen a decade of unprecedented change.
信息技术的飞速发展对现代数学教育产生了深刻的影响，使得数学教学面貌发生了前所未有的变化。
The information flies technically to develop to bring about deep influence on modern mathematics education soon, making mathematics teaching feature take place the unprecedented variety.
从图书馆目录的功能、编目范围和检索特点所体现的内涵和外延的变化，可看出图书馆的编目、检索也发生了前所未有的变化。
They are embodied in the changes of catalogue function, cataloguing range and retrieval features, from which unprecedented changes in cataloguing and retrieval can also be seen.
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