当
讲解
"当...的时候" 用来表示某个动作或事件发生的时间背景，通常引导一个时间状语从句，说明主句动作发生的具体时间。
"当...的时候" (dāng...de shíhòu) is used to indicate the time background when a certain action or event occurs. It typically introduces a temporal adverbial clause, explaining the specific time when the main clause action happens.
例句
当他进来的时候，我们正在看电视。
When he came in, we were watching TV.
当爸爸回来的时候，妈妈已经做好晚饭了
When Dad came back, Mom had already made dinner.