lit. mustn't speak of two things on the same day (idiom); not to be mentioned in the same breath
incomparable
Definitions (粵典–words.hk)
語句
冇得比較;冇條件相提並論 not to be mentioned in the same breath; literally: can't speak of the two things on the same day
幾十年前同而家嘅科技發展不可同日而語。
几十年前同而家嘅科技发展不可同日而语。
gei2 sap6 nin4 cin4 tung4 ji4 gaa1 ge3 fo1 gei6 faat3 zin2 bat1 ho2 tung4 jat6 ji4 jyu5. It does not make sense to mention the technological development of decades before and nowadays in the same breath.
Definitions (Wiktionary)
phrase, idiomatic
incomparable; too different to compare; cannot be mentioned in the same breath; there is no comparison between them