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in a line; in a row
商品がずらっと棚に並んでいたよ。
Products were lined up in a row on the shelf.
本がずらっと本棚に並べられている。
Books are lined up neatly on the bookshelf.
店の前にずらっとお客が並んでいる。
Customers are lined up in a row in front of the store.