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among themthe great advances that had been made in the field of _____and the search foralternatives to natural resources like ivory.example 3： despite their cost.原文当中的gaining in popularity题目中用morepopular than they used to be作为替换，原文：biologically，原文当中的biol
温馨提醒：随时光变迁，文中所陈述观点；准确性、难免有所变动，因此文中观点仅供参考。
