when
01
什么时候, 何时
used when we want to ask at what time something happens
例子
Can you tell me when the meeting begins?
你能告诉我会议什么时候开始吗？
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
I always eat breakfast when I wake up in the morning.
我早上醒来时总是吃早餐。
02
当, 而
used to imply unexpected or ironic outcomes
例子
She found hope when all seemed lost.
当一切似乎都失去时，她找到了希望。
03
当
used to provide a reason or explanation for the main clause
例子
It does n't make sense to spend so much money on a new phone when my current one works perfectly fine.
当我现在的手机完全好用的时候，花这么多钱买一部新手机是没有意义的。
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 remember when we went to Paris.
我记得当我们去巴黎的时候。
