ものだ details
write + that's just how it is
kaku mono da
that's just how it is; you really should; used to do
人は誰でも間違えるものだ。
hito wa dare demo machigaeru mono da.
Everyone makes mistakes, that's just how people are. neutral
子供のころ、よくこの川で泳いだものだ。
kodomo no koro, yoku kono kawa de oyoida mono da.
When I was a kid, I used to swim in this river all the time. neutral
- colloquial
- past
- polite
- negative
Examples
that's just how it is; you really should — a general truth about how things naturally are, or a mild norm-based admonition
人は誰でも間違えるものだ。
hito wa dare demo machigaeru mono da.
Everyone makes mistakes, that's just how people are. neutral
挨拶ぐらいちゃんとするもんだよ。
aisatsu gurai chanto suru mon da yo.
You really ought to at least say a proper hello. casual
年を取ると、体のあちこちが痛くなるものです。
toshi o toru to, karada no achikochi ga itaku naru mono desu.
As one gets older, one's body naturally starts aching here and there. neutral
人の悪口を言うものではない。
hito no waruguchi o iu mono de wa nai.
You shouldn't speak ill of others. neutral
used to do — a nostalgic remark about a habit or state that no longer holds
子供のころ、よくこの川で泳いだものだ。
kodomo no koro, yoku kono kawa de oyoida mono da.
When I was a kid, I used to swim in this river all the time. neutral
若い時は、朝まで平気で遊んだもんだよ。
wakai toki wa, asa made heiki de asonda mon da yo.
Back when I was young, I used to stay out having fun till morning without a second thought. casual
Formation
{V}ものだattaches to dictionary formi-adj + ものだ（つらいものだ）attaches to i-adjectivena-adj + なものだ（不思議[ふしぎ]なものだ）attaches to na-adjective{V-ta}ものだattaches to た-form
Variant notes
- もんだ — casual contraction, spoken only — 疲[つか]れるもんだ, よく叱[しか]られたもんだ.
Notes
できたものだ can mean either "that used to happen" or "what a job, well
done." Genuinely だ-less もの is a different word entirely (んだもの,
ものか), not this pattern's stripped form.
Related patterns
Similar
べきだ verdicts a specific situation from a rule the speaker is applying right now ("you should do X here"), while ものだ's advisory reading states a general norm about how things are done as a matter of course — べきだ argues a case, ものだ recites a custom.
たことがある states a bare fact of experience, true once and still available now (行ったことがある); ものだ's nostalgia sense claims the action was a repeated HABIT in a period now closed (よく行ったものだ) and carries wistfulness たことがある never does.