当时 (dāngshí)

当时 refers to a specific moment in the past that has already been mentioned or is understood from context, meaning "at that time" or "back then."

Meanings

[adverb] At that time; then; at the time (refers to a past moment in context).
[noun] That time; that moment (used as a time noun).

Example Sentences

我当时不知道他已经离开了。 Wǒ dāngshí bù zhīdào tā yǐjīng líkāi le. At that time, I did not know he had already left.

当时的情况非常复杂。 Dāngshí de qíngkuàng fēicháng fùzá. The situation at that time was very complicated.

他当时才二十岁，但已经很有经验了。 Tā dāngshí cái èrshí suì, dàn yǐjīng hěn yǒu jīngyàn le. At the time, he was only twenty years old, but already very experienced.

我们当时都很高兴，没想到后来发生了那些事。 Wǒmen dāngshí dōu hěn gāoxìng, méi xiǎngdào hòulái fāshēng le nàxiē shì. We were all very happy at the time; we had no idea what would happen later.

Collocations

Collocation	Meaning
当时的情况	the situation at that time
当时决定	decided at that time
回想当时	looking back at that time
就在当时	right at that moment

Usage Notes

当时 always refers to a past time already established in the conversation or text. It cannot refer to the present or future. For the present moment, use 此时 or 现在; for a future moment, use 到时候 or 那时.

Memory Hook

当 means "at the time of" and 时 means "time"; 当时 points directly to a specific moment in the past, like a finger on a timeline.