one foot in the grave字面意思一脚已经入了坟，引申为风烛残年；行将就木；半截入土。

【例句】
That old rock star has one foot in the grave. He's been a heavy smoker and drinker for years.
那个年老的摇滚巨星已是风烛残年。他已经喝烟酗酒很多年了。

The sick old man knew he had one foot in the grave.
患病的老人知道他已经半截入土了。