https://online2.tingclass.net/lesson/shi0529/0009/9907/641.mp3
https://image.tingclass.net/statics/js/2012
in the middle of 正忙于...，在…时期
I am in the middle of some very important work.
我在忙一些重要工作呢。
Mike is in the middle of a meeting. Call him later.
麦克在开会呢，你一会再打给他吧。
