Copy these lists into a map with each list entry identified by the first word (the key) of the list.
将这些列表复制到一个映射且使用列表的第一个单词(键)标识每个列表条目。
2
You then iterate over the list from the stories with the given tag, putting each into the map using the ID of the story as the key.
然后循环遍历列表获得带有特定标记的新闻，并以每条新闻的ID为键将它们放入映射中。
3
You could use a List or a Map to implement the relationship; however, a Map offers the advantage that it can provide fast lookup given, say, the book catalog number as the key.