at

We agreed to meet at the entrance of the museum at noon.

(Chinese) 我们约定中午在博物馆门口见面。

The scientist spent years working at the research laboratory.

(Chinese) 这位科学家在研究实验室工作了多年。

The international flight is scheduled to depart at 10:30 PM.

(Chinese) 这架国际航班定于晚上10:30起飞。

Most people in this office start their work day at 9 o'clock.

(Chinese) 这家办公室的大多数人从9点开始一天的工作。

Pure water boils at sea level at 100 degrees Celsius.

(Chinese) 纯水在海平面高度的沸点是100摄氏度。

The fruits are currently on sale at half price.

(Chinese) 这些水果目前正以半价促销。