妹(いもうと) imoutoは wa３ 3歳(さい) sai年(とし)下(した) toshishitaで de弟(おとうと) otoutoは wa４ 4歳(さい) sai年(とし)下(した) toshishitaです desu。 My younger sister is 3 years younger and my brother is 4 years younger. Literal Younger-sister [topic-は] 3-years younger-and younger-brother [topic-は] 4-years younger. 年下 ('younger by X years') is the standard way to express relative age — X歳年下 ('X years younger'). で links the two clauses coordinately. The sentence efficiently packs two family facts into one statement. family
妹(いもうと) imoutoは wa３ 3歳(さい) sai年(とし)下(した) toshishitaで de弟(おとうと) otoutoは wa４ 4歳(さい) sai年(とし)下(した) toshishitaです desu。 My younger sister is 3 years younger and my brother is 4 years younger. Literal Younger-sister [topic-は] 3-years younger-and younger-brother [topic-は] 4-years younger. 年下 ('younger by X years') is the standard way to express relative age — X歳年下 ('X years younger'). で links the two clauses coordinately. The sentence efficiently packs two family facts into one statement. family