run into someone

To encounter someone by chance.

偶然遇到某人

Oh, I didn't tell you that I ran into Mary when I was at the movie theater.

噢，我没告诉你我在电影院碰见玛丽的事

Everyone comes from all over town to this market on the weekend, so you never know who you might run into.

周末，城里各地的人都来到这个市场，所以你永远不知道会遇到谁。