This is the 4690th most frequent Chinese word.
當
"當" means "to act as," "to face," "to take on," or "at the time of" depending on context.
使用“當”作为动词，表示充当或担任某个角色。
他在會議上當主席。
He served as the chairman in the meeting.
使用“當”作為连词，表示时间的从句。
當我年輕時，我喜歡旅行。
When I was young, I liked traveling.
使用“當”作为前缀，形成副词“當然”，表示一种确定性。