他的父亲是一位著名的历史学家。

His father was a famous ___historian.

我非常愿意帮助历史学家们解开泰国起源之谜。

I would be very willing to help ___historians solve the enigma about the origin of Thailand.

作为一名历史学家，她专攻中世纪欧洲史。

As a ___historian, she specialized in medieval European history.