So imagine I get asked this question, perhaps when calling someone:
図書館...何をしている。 Perhaps I am reading a book, so: ［僕は］としょかん...本を読んでいる。 Here is
the problem. For "...", I am conflicted on whether to use で or に in each
instance and in general. I know that being at a location is に, and doing an
action at a location is で, but what of this sentence pattern? Are there
specific cases for whether to use one or the other?
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2019-08-20T01:46:44.520
70214
2020-10-24T14:04:05.437
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question
particles
Particle Use When Using Form V-ている/ある at a Location: で or に?
You are talking about some action that is taking place in the 図書館, so you have
to use で.

> 図書館 **で** 本を読んでいます。

  * [Particles: に vs. で](https://japanese.stackexchange.com/q/60/5010)

There is a subsidiary verb いる used to express progressive "-ing", but it
doesn't interfere with this rule.
CC BY-SA 4.0
2019-08-20T02:01:57.280
70215
2019-08-20T02:01:57.280
5010
70214
answer