书名：疾天New Toeic阅读超高分
版本：2019/7初版
页数：p.49 第111题
题目：
Due to the high volume of foot traffic, the shop must polish its
floors more_______ than usual during the peak season.
(A) frequent
(B) frequented
(C) frequency
(D) frequently
疑问：为什么是D而不是A