下面这句话中 worth 是名词使用方法吗？为何前面的 days 无需写成“所有格”？
例句1、The metal lunch box craze lasted until themid-1980s, when plastic took over. Two theories exist as to why. The first—and most likely—is that plastichad simply become cheaper. The second theory—possibly an urban myth—is that concernedparents in several states proposed bans on metal lunch boxes, claiming kidswere using them as “weapons” to hit one another. There's a lot on the internetabout a state-wide ban in Florida,but a few days worth of digging by a historian at the Florida State HistoricalSociety found no such legislation. Either way, the metal lunch box was out.——《大学习英语等级考试》
下面这句话也是：
例句2、 I gave him sixpence yesterday and advised him tosave it. Instead, he bought himself sixpence worth of trouble. ——《新定义英语》
不是说这样的情况要用下面这种使用方法吗？
名词's worth of +名词（为名词使用方法，意思价值为...的某物）
I went and bought about six dollars' worth of potato chips.
1 《韦氏高阶》、《牛津》等词典觉得这个结构要用属格名词。比如：
He bought 40 dollars' worth of gas. 韦氏
She has 15 years' worth of experience inadvertising. 韦氏
The winner will receive fifty pounds' worth ofbooks. 牛津
2 柯林斯词典则给出二种使用方法，即属格形式和连字符形式。比如：
I went and bought about six dollars' worth ofpotato chips.
The prepaid sim card gives you ten euros-worth ofcalls.
You've got three years' worth of research moneyto do what you want with.
The film is his own compilation of more than 50hours-worth of footage.
3 WR网站中母语为英语的老外们对此看法不一，有人虽然同意用属格形式，但觉得这种使用方法正在消失，更多的人目前直接用复数名词修饰worth，不需要属格。https://forum.wordreference.com/threads/four-million-dollars-worth-of-equipment.619426/
4 从网友的这篇文章与《新定义英语》中不需要属格，可以了解目前直接用复数名词修饰worth而不需要属格，已经是非常容易见到的现象了。
