给定一个段落和单词，用该单词替换该段落中的所有出现次数。
段落：“Jack and Jill went up the hill to fetch a pail of water. Jack fell down and broke his crown, and Jill came tumbling after.”
单词：“bucket”
段落改写后为：“Jack and Jill went up the hill to fetch a bucket of water. Jack fell down and broke his crown, and Jill came tumbling after.”