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lost property; something dropped and left behind
dropping something (without realising); losing something
駅で落とし物をして交番に届け出た。
I lost something at the station and reported it to the police box.
落とし物の傘を取りに窓口へ行った。
I went to the counter to pick up my lost umbrella.
落とし物が見つかって本当に助かった。
I was really relieved that my lost item was found.