试题题干
According to the records available, human beings have been engaged in the study of language for（ ）centuries.
参考答案
正确答案：
试题解析
根据现有的记录，人类从事语言研究已经有25个世纪了。
According to the records available, human beings have been engaged in the study of language for（ ）centuries.
根据现有的记录，人类从事语言研究已经有25个世纪了。