tf(t in d) 与term的出现次数（frequency）有关系（correlate to），定义为（defined as）term t在当前打分（currently scored）的文档d中出现（appear in）的次数（number of times）。
2
?被解释为
... defer to 遵从，听从，服从 defined as被解释为，被定义为 depart form 背离，违反 ...
3
?规定为
...hicken is an extremely good choice.The student will dig up the chicken to bring back to the family, 规定为 ? Defined as 你知道他们中间有多少人参加讨论了吗？ ? Your did know them how many participants discussed?