在英语语法中，when和while都可以用来引导时间状语从句，但它们的使用场景和含义有所不同。了解它们的区别并熟练运用是学习英语的重要一步。接下来，我们将详细探讨when和while的不同之处，并通过一些专项练习题来帮助巩固知识。

一、When的用法

1. 表示“当……的时候”

When可以用来表示一个动作发生的同时，另一个动作也在进行。它强调的是某个特定的时间点或事件发生时的情况。

例句：

- When I was young, I loved playing outside.

（当我年轻的时候，我喜欢在外面玩。）

2. 引导条件状语从句

When也可以用于表达条件，类似于if的用法。

例句：

- When you finish your homework, you can go out to play.

（当你完成作业后，你可以出去玩。）

二、While的用法

1. 表示“在……期间”

While强调的是一个时间段内的持续性动作，通常表示两个动作同时发生。

例句：

- While I was reading, my sister was watching TV.

（在我读书的时候，我妹妹正在看电视。）

2. 表示对比

While还可以用来表示对比关系，相当于“然而”或“而”。

例句：

- She is outgoing while her brother is shy.

（她很外向，而她哥哥却很害羞。）

三、专项练习题

以下是一些练习题，帮助你更好地掌握when和while的用法：

1. When he arrived at the station, the train had already left.

A) He missed the train.

B) He caught the train.

C) The train was late.

2. While I was studying for my exam, my phone kept ringing.

A) I ignored the calls.

B) I answered all the calls.

C) The calls were important.

3. When it rains, I usually take an umbrella.

A) I don't like getting wet.

B) I enjoy walking in the rain.

C) I always forget my umbrella.

4. While she was cooking dinner, her husband was setting the table.

A) They were preparing for a party.

B) They were eating out.

C) They were having a picnic.

5. He was sleeping when the alarm went off.

A) He woke up immediately.

B) He ignored the alarm.

C) He turned off the alarm.

四、答案解析

1. A) He missed the train.

2. A) I ignored the calls.

3. A) I don't like getting wet.

4. A) They were preparing for a party.

5. A) He woke up immediately.

通过以上练习题，相信你对when和while的用法有了更深刻的理解。在实际应用中，多加练习和积累经验是非常重要的。希望这些内容能对你有所帮助！