一、基本结构对比

when引导时间状语从句，强调“某个短暂时间点或事件发生时”

while引导时间状语从句，强调“两个动作同时进行或存在对比”

二、合并造句示例

主句进行时，从句过去时

- When I was reading a book, the teacher came in.

- 同义改写：While I was reading a book, the teacher came in.

主句过去时，从句过去进行时

- When the movie started, we were already eating dinner.

- 同义改写：While the movie started, we were already eating dinner.

主句过去完成时，从句过去时

- When the meeting began, we had already finished the task.

- 同义改写：While the meeting began, we had already finished the task.

三、注意事项

两种连词可互换使用，但语义侧重点不同。例如：

"When" 可以表示“就在那时”，如：When she arrived, the party started.

"While" 强调主从句动作的持续性或对比，如：

- While he was studying, the phone kept ringing.

四、易混淆点

避免混淆：

当需要表达“主句动作在从句动作之前完成”时，必须使用过去完成时：

- I had finished my homework when my friend called.

而非简单过去时：

- I finished my homework when my friend called.

通过以上示例，可以看到"when"和"while"在时间状语从句中的灵活运用，需根据动作发生的时间关系选择合适的连词。