按类别处理

PLAIN

收集一个dict，先过这个dict，有命中则替换。
无命中则直接将输入输出。

PUNCT

因为训练集中所有的PUNCT都是自己本身，所以直接将输入输出。

DATE

样例

22 September 2015 -> the twenty second of september twenty fifteen
2006 -> two thousand six
April 10, 2013 -> april tenth twenty thirteen
11/17/09 -> november seventeenth o nine
2007-11-24 -> the twenty fourth of november two thousand seven
25-08-2015 -> the twenty fifth of august twenty fifteen
14 April -> the fourteenth of april
June 2004 -> june two thousand four