HSK 2 grammar · pattern
该…了
该…了 — it's time to …
Pattern
+ + +
( ) can be left out · other words may come before, between and after
How it works
该 … 了 says the time has come for something — "it's time to …". 该 marks what should happen now and the sentence-final 了 signals the new situation.
Examples
很晚了,该睡觉了。
Hěn wǎn le, gāi shuìjiào le.
It's late; time to sleep.
该上课了。
Gāi shàngkè le.
It's time for class.
我们该走了。
Wǒmen gāi zǒu le.
It's time for us to go.
Related

See it in a story
In the app, 该…了 is underlined wherever it appears in the stories you read, and practised with sentences from them. Free.