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> So Person A says: `どうしたんですか？`
>
> Person B replies: `忘れ物をしたんです。`

I'm not understanding `した` in this sentence. `忘れ物` means `something left
behind or forgotten`. So I translate `忘れ物をした` as `did forgotten-thing`. Which
makes little sense. So how am I to translate or make sense of `した`'s use here?
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2016-09-30T23:31:49.973
39591
2016-10-08T15:53:50.513
2020-06-17T08:18:27.500
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words verbs
What does する mean here?
忘れ物 is a noun, so you have to add する to make it a verb.

You can take it together to mean: _"I forgot something."_

A similar example is 食べ物, literally translated as "thing to eat" or "eating-
thing". So in the same way you would say: 食べ物を食べた。 - _I ate something_ not _I
ate something to eat_.
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2016-10-01T00:10:02.637
39593
2016-10-01T00:10:02.637
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する here is a [light verb](https://en.wikipedia.org/wiki/Light_verb), which
means you basically have to memorize which verb should be used with which
noun.

In Japanese, 忘れ物 is a noun which is always used with する, and 忘れものをする is a very
common way to say "forget/leave something". You have to memorize this.

English also has verb usages which are almost unpredictable for learners. In
English you can say "do the dishes" to mean washing dishes, but Japanese
people never say 皿をする. See [this
question](https://ell.stackexchange.com/q/42909/8629), too.
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2016-10-01T02:38:31.687
39597
2016-10-01T03:55:39.607
2017-04-13T12:55:20.437
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According to the dictionary, 忘れ物 can also be used as a verb:  
<http://dictionary.goo.ne.jp/jn/238200/meaning/m0u/%E5%BF%98%E3%82%8C%E7%89%A9/>

So 忘れ物をする means "to forget something, to leave something behind".

I agree with you that literally the expression doesn't make sense, but it is
listed in the dictionary.
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2016-10-08T15:53:50.513
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