他半夜肚子疼，去医院看医生了。

Tā bànyè dùzi téng, qù yīyuàn kàn yīshēng le.

His stomach hurt at midnight, so he went to the hospital to see a doctor.

他常常工作到半夜才回家。

Tā chángcháng gōngzuò dào bànyè cái huíjiā.

He often works until midnight before going home.

你半夜还在看电视吗？

Nǐ bànyè hái zài kàn diànshì ma?

Are you still watching TV in the middle of the night?