ものだ | That's How It Is in Japanese

Four Jobs, Sorted by Form

ものだ is doing several unrelated things, and the verb form tells you which.

1. A general truth. Dictionary form.

• 時間(じかん)は早(はや)く過(す)ぎるものだ。(Time passes quickly — that's how it is.)

2. Nostalgia. た form, about the repeated past.

• 子供(こども)の頃(ころ)よく遊(あそ)んだものだ。(We used to play a lot as children.)

3. Mild obligation. Dictionary form, about what people ought to do.

• 年上(としうえ)は敬(うやま)うものだ。(One should respect one's elders.)

4. Exclamation. Often with よく or なんて.

• よく覚(おぼ)えていたものだ。(How well you remembered!)

Telling 1 From 3

Both use the dictionary form, and the difference is whether the sentence describes the world or prescribes behaviour. If you can insert "as a rule, people ought to", it is sense 3.

ものではない — The Negative

The negative is only the obligation sense — a prohibition on general grounds:

• そんなことを言(い)うものではない。(That's not the sort of thing one says.)

Not もの as an Excuse

Sentence-final もん / もの is a different thing entirely — a childish or intimate excuse: だって知(し)らなかったもん。(But I didn't know!)