people watching

基本解释

You watch the people watching you.
看那些观察你的人。
The people watching below are tense and trembling with their hearts in their mouths.
下面看的人悬心吊胆，心惊肉跳。
《新英汉大辞典》
People Watching – Sitting there on your bench you can see people in every direction.
观察人们——坐在长椅上，你可以看到各个方向的人们。

Many of the people watching "The Nutcracker" that night did not like the ballet either and criticized it.
The way we teach this class is we're going to play games, we're going to have discussions, we're going to talk among the class, and you're going to be learning from each other, and I want you to help people watching at home to be able to learn too.
课堂上我们通过做游戏来博弈,课上会有随堂讨论,课堂交流,我们相互学习,这样看视频的学生,也能收到良好的教学效果
耶鲁公开课 - 博弈论课程节选
Just lots of good food and lots of things to see, lots of people watching, you know,
有很多好吃的和好看的（人和物），
在中央公园溜达 - SpeakingMax英语口语达人

There are millions, tens of millions of people watching this broadcast right now, Mr. President.
WHITEHOUSE: BiPartisan Super Bowl Party