"Good afternoon" is a commonly used greeting in Engpsh to greet people in the afternoon. It originated from the traditional way of greeting someone during the specific time period of the day.
Examples:
Good afternoon, how can I help you today?
It's a lovely afternoon, isn't it?
Translation: 下午好！
Note: "Afternoon" typically refers to the period of the day between noon and evening, which is usually around 12pm to 6pm.