现在有一个英文字典（每个单词都是由小写的 a - z 组成），单词量很大，达到100多万的单词，而且还有很多重复的单词。

　　此外，我们现在还有一些 Document，每个Document 包含一些英语单词。

　　针对这个问题，请你选择合适的数据结构，组织这些数据，使时间复杂度和空间复杂度尽可能低，并且解决下面的问题和分析自己算法的时间复杂度。 -Now an English dictionary (each word are lowercase ' a' -'　z ' ), a large amount of words, to reach more than 100 million words, and there is a lot of repetition of words. In addition, we have some of the Document, each Document contains some English words. To address this issue, you select the appropriate data structure, the organization of these data, the time complexity and space complexity as low as possible and solve the following problem and analyze the time complexity of their algorithm.