https://online2.tingclass.net/lesson/shi0529/0009/9907/577.mp3
https://image.tingclass.net/statics/js/2012
讲解文本：
top dog 胜利者，最棒的人，处于领导地位的人
My boss is the top dog at my office.
我老板是我们办公室里最牛的人。
Mike is young, but he is a top dog in his company.
麦克虽然年轻，在公司却位居要职。
