when
01
什么时候, 何时
used when we want to ask at what time something happens
语法信息
不可比较
疑问副词
例子
Can you let me know when the package arrives?
你能告诉我包裹什么时候到吗？
02
何时, 当
used to refer to a specific situation or time
when
01
当, 在...的时候
used to indicate that two things happen at the same time or during something else
例子
He felt nervous when he had to give a presentation.
他当不得不做演示时感到紧张。
02
当, 而
used to imply unexpected or ironic outcomes
例子
He laughed when others expected him to be angry.
当别人以为他会生气时，他笑了当。
03
当
used to provide a reason or explanation for the main clause
例子
I don't understand why we need to rush when we still have plenty of time to finish the project.
我不明白为什么我们需要匆忙当我们还有很多时间来完成这个项目。
when
01
什么时候
used to represent the time when something happens as the subject or object of verb or preposition
例子
I don't know when he'll arrive.
我不知道他什么时候会到。
