Expressing "When" Using "当...的时候”
当dāng…的时候de shíhou means "when," very similar to just using 的时候de shíhòu or 时shí. We can use ”时shí” to indicate ”的时候 de shíhou”.
当dāng + Clause + 的时候de shíhou / 时shí，…
Dāng tā liù suì de shíhòu, tā jiù yǐjīng hé bàba zuòguò fēijīle
当他六岁的时候，他就已经和爸爸坐过飞机了。
When he was six years old, he had already flown on a plane with his dad.
Dāng wǒ kàn dào zhè zhāng zhàopiàn shí, wǒ xiǎngdàole wǒmen de dàxué shēnghuó.
当我看到这张照片时，我想到了我们的大学生活.
When I saw this photo, it reminded me of our college life.
Dāng wǒ yīge rén zàijiā chīfàn shí, huì biān chīfàn biān kàn shìpín.
当我一个人在家吃饭时，会边吃饭边看视频。
When I eat alone at home, I like to watch videos while eating.
Dāng tā nánguò de shíhòu, tā huì fēicháng xiǎng chī bīngqílín.
当他难过的时候，他会非常想吃冰淇淋。
When he feels sad, he really wants to eat ice cream.
Dāng nǐ yǒu kòng de shíhòu, jìdé gěi wǒ dǎ diànhuà.
当你有空的时候，记得给我打电话。
When you have free time, remember to give me a call.
＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿
What's the difference between '当dāng…时shí/的時候de shíhou' and '...时shí/的时候de shíhou'?
Note 1 : Compared to '…时shí/的時候de shíhou', '当dāng...时shí/的时候de shíhou' is more formal.
Note 2 : A noun CANNOT be used in the structure '当dāng…时shí/的時候de shíhou'.
Dāng qiūtiān de shíhòu, wǒ huì huílái kàn nǐ.
❎ 当秋天的时候，我会回来看你。-> 秋天qiūtiān is a noun and can't be used in the structure “当dāng…时shí/的時候de shíhou”.
When autumn comes, I will come back to see you.
Qiūtiān de shíhòu, wǒ huì huílái kàn nǐ.
✅ 秋天的时候，我会回来看你。
In autumn, I will come back to see you.
Dāng qiūtiān lái de shíhòu, wǒ huì huílái kàn nǐ.
✅ 当秋天来的时候，我会回来看你。-> 秋天来qiūtiān lái is a clause and can be used in the structure “当dāng…时shí/的時候de shíhou”.
When autumn arrives, I will come back to see you.
Dāng liǎng diǎn de shíhòu, gěi wǒ dǎ diànhuà.
❎ 当两点的时候，给我打电话。-> 两点liǎngdiǎn is a noun and can't be used in the structure “当dāng…时shí/的時候de shíhou”.
Give me a call at two o'clock.
Liǎng diǎn de shíhòu, gěi wǒ dǎ diànhuà.
✅ 两点的时候，给我打电话。
At two o'clock, give me a call.