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preliminary investigation; preliminary inquiry
preparation (for a class); going over one's lessons (in advance); studying ahead
プロジェクトのために下調べを行った。
Conducted preliminary research for the project.
旅行前に下調べをしっかりしておく。
I'll do thorough preliminary research before the trip.
下調べをきちんとすることが大事だ。
It's important to do thorough preliminary research.