每天重复同样的工作让他感觉像是在完成一项永无止境的任务。

Repeating the same work every day felt like a ___Sisyphean task to him.

清理沙滩上的塑料垃圾是一项徒劳的工作，因为海浪总会带来新的垃圾。

Cleaning plastic waste from the beach is a ___Sisyphean task, as the waves always bring new trash.