睡着

shàng kè shuì zháo

上课睡着

go to sleep while having a lesson

kàn shū shuì zháo le

看书睡着了

sleep over one's book

wǒ lèi jí le zài shā fā shang shuì zháo le

我累极了，在沙发上睡着了。

I was so tired I crashed out on the sofa.

wǒ tīng jiàn hān shēng zhī dào tā shuì zháo le

我听见鼾声，知道他睡着了。

I heard a snore and knew he'd fallen asleep.