He goes to the library once a weekonce a week 提问

问题描述:

He goes to the library once a week
once a week 提问

once a week是表示频率的,所以提问就问他多久去一次:How often does he go to the library?

他每周去一次图书馆!once a week 每周一次!由此类推序数词加段时间意为每多长时间多少次!手机打的很累啊…

how often does he go to library

一周一次
(他一周去一次图书馆)