He goes to see his parents per week?对per week 划线提问怎么写?

题目

He goes to see his parents per week?对per week 划线提问怎么写?
要解释的!别给个空答案!那样别人别挺他!

答案

how often does he go to see his parents?
per week是每个星期,问的是频率,所以用how often