"Mr. Rigot carried a box into the kitchen. Then he placed the box on the counter."
In the first sentence, it is unspecified which particular box is being referred to. It could be any box. However, in the second sentence, after having identified the box previously, "the" is used to indicate that it is indeed the same box as before.
In the first sentence, it is unspecified which particular box is being referred to. It could be any box. However, in the second sentence, after having identified the box previously, "the" is used to indicate that it is indeed the same box as before.
by The Maddest Hatter December 11, 2010