同学你好，该知识点来自沪江网校《新概念英语3、4册连读【随到随学班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好~
因为这里tired out with a hard week's sweat and effort是形容词短语，形容的是前面labourer的状态，所以是定语。过去分词做后置定语前面可以有逗号。如：
The business, founded by Dawn and Nigel, suffered financial setbacks.唐和奈杰尔创办的企业在资金上遇到了一些问题。

tired是形容词。
They were cold, hungry and tired out (= very tired) .
他们又冷又饿，疲惫不堪。

getting tired 正在变得很疲惫，意思不对。

祝同学学习进步~