for years on end; year after year ❍ ～，殚精竭诚，成书一帙，名曰《官场现形记》。(鲁迅《中国小说史略》254) He has spent months and years,sparing no pains,to write this Exposure of the Official World.
穷年累月qiónɡ nián lěi yuè
穷：尽，穷年：年初到年终；累：积累；累月：持续几个月。形容时间长久，年复一年，接连不断。year after year, for years on end