A primary source is a document that was created at or near the time being studied, often by the people being studied.
第一手来源是当要或者接近被研究的时候创建的一个文档，常常被人们用于研究。
A primary source is a document that was created at or near the time being studied, often by the people being studied.
第一手来源是当要或者接近被研究的时候创建的一个文档，常常被人们用于研究。
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