引用Pdawiki(存档)的一条校订：
英汉大词典 第2版 陆谷孙
【hard labour】
be sentenced to two year’s hard labour 被判处服两年苦役
【two year’s】应是【two years’ 或 two years of … / two years at …】
参考：
新世纪 胡壮麟
The sentence of the court was twelve years’ hard labour, to be served in a British prison. 法庭的判决是在一所英国监狱中服12年苦役。文馨
He was condemned to five years’ hard labor. 他被判五年的苦役。韦高
He was sentenced to five years of hard labor. [=time in prison spent in intense physical labor] 他被判处服劳役五年。新时代 张柏然
He was convicted to 10 years at hard labour. 他被判服10年苦役。《柯林斯》：
The sentence of the court was twelve years’ hard labour, to be served in a British prison.
法庭判其在一所英国监狱里服12年苦役。
用Emditor打开《英汉大词典》的mdx源文本，Search - Find“year’s”，点按Extract
又发现一个问题：
【firstfruits】
This book is the firstfruits of many year’s study.
[校记]“many year’s”当作“many years’”
在本坛的tio中检索many years’
a friendship of many years’ standing
多年的友情 牛津高阶
a marriage of many years’ standing
持续多年的婚姻 韦氏高阶
25 years’ standing, many years’ standing, etc.
已持续 25 年、多年等 牛津搭配