把下列句子改成特殊疑问句 He plays football once a week.
问题描述：
把下列句子改成特殊疑问句 He plays football once a week.
once a week 划线
答
How often does he play football?为什么有often？once a week是频率副词 对这一部分提问时用how often是固定搭配