释义
n.
a person who is particularly skilled at a specified activity or art
行家，能手
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he's a past master at keeping his whereabouts secret .他非常善于隐瞒自己的行踪。
a person who has held the position of master in an organization
前会长，前主席
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he was a past master of the City Company of Grocers .他是市百货公司的前董事长。