1. I〔深く掘る〕dig (down)
  1. II〔検討する〕dig into; delve into
    • 問題を深く掘り下げる
    • probe deeply into a matter/dig [get] to the bottom of a matter
    • その問題はもっと掘り下げてみる必要がある
    • We need to look into the matter more deeply./The matter needs further investigation.