Coming to buy coffee mugs with 〜に来る

Grammar Explanation: Coming to for a purpose with 〜に来る

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Rize explains to Syaro why she and her friends are at the store.

リゼ:: 「喫茶店(きっさてん)で使(つか)うカップ買(か)いに来(き)たんだよ」; “We came to buy cups to use at the café.”