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gyudon; rice covered with sliced beef, usu. with fried onion
お昼は牛丼を食べました。
I had gyudon for lunch.
学生にとって、牛丼は安くて早い食事です。
For students, gyudon is a cheap and quick meal.
家で牛丼の味を再現するのはなかなか難しいです。
It's quite difficult to recreate the taste of gyudon at home.