回答

・visiting day
・open day

「參觀日」英文可以表達為visiting day或open day。

Today is my child's school visiting day.
（今天是我孩子的學校參觀日。）

Today is my children's elementary school open day, so I want to see both my eldest son and my second son's classes as scheduled.
（今天是我孩子們的小學參觀日，所以我想按照日程去看看我的大兒子和二兒子的班級。）

有幫助｜0