century用不用复数
你的翻译是对的,因为这是定语从句,所以翻译成...的法语.
但是在从句里,谓语的单复数不是由主句里的先行词（French）决定的,而是由从句里的主语决定的.
分成两个单句是这样的：
主句：Their language is basically seventeenth-century French.
从句：English,Spanish and Italian words have been added to (which = French).
可见从句中french不是做主语的,对谓语动词的单复数没有影响,只有主语words决定谓语.
century的复数
century的复数形式是变y为i再加es,即centuries。1、N-COUNT 世纪 A century is a period of a hundred years that is used when stating a date. For example, the 19th century was the period from 1801 to 1900.celebrated figures of the late eighteenth century.18世纪晚期的名人2、N-COUNT 一百年 A century is any period of a hundred years.The drought there is the worst in a century.这是一百年来最严重的旱灾。3、N-COUNT (板球中一名击球手获得的)一百分，一百多分 In cricket, a century is a score of one hundred runs or more by one batsman.
