https://online2.tingclass.net/lesson/shi0529/0009/9884/80.mp3
https://image.tingclass.net/statics/js/2012
drop in 顺便拜访;顺便进入
drop in on somebody 顺便拜访某人
drop in at someplace 顺便拜访某地
例句：
The Wilsons dropped in on us just as we finished dinner.
威尔森一家在我们刚吃完晚饭时就突然拜访。
Please drop in on us when you happen to be free.
如果你碰巧有空，请到我的办公室来。
末尾音乐：
I Go In
