Completed actions with 了 — Chinese grammar (HSK 1)

Subject + Verb + 了 + Object / Sentence + 了

了 (le) after a verb shows the action is completed, which often matches the English past tense but is really about completion rather than time. It can sit right after the verb or at the end of the sentence. To say something did not happen, use 没有 before the verb and drop 了 entirely.

Examples

我买了三本书。 Wǒ mǎi le sān běn shū.	I bought three books.
他昨天回家了。 Tā zuótiān huí jiā le.	He went home yesterday.
你看那个电影了吗？ Nǐ kàn nà ge diànyǐng le ma?	Did you watch that movie?

Tip: 了 is not a past-tense marker; 我没有买了书 is wrong, say 我没有买书.