monotonous

Working on the assembly line can be very monotonous, as you do the same task all day.

(Chinese) 在流水线上工作可能非常枯燥，因为你整天都在重复同样的任务。

The speaker's monotonous voice made it very difficult for the audience to stay awake.

(Chinese) 演讲者那单调乏味的声音让听众很难保持清醒。