3 sentences

1. 学校规定晚上十一点准时熄灯。

   xué​xiào guī​dìng wǎn​shang shí​yī​diǎn zhǔn​shí xī​dēng.

   School regulations state that it's lights out at 11:00 PM sharp.

   Source: Dong Chinese Dictionary

2. 十点熄灯。

   shí​diǎn xī​dēng.

   Lights out at 10.

   Source: OpenSubtitles

3. 离开房间前请记得熄灯。

   lí​kāi fáng​jiān qián qǐng jì​de xī​dēng.

   Please remember to turn off the lights before leaving the room.

   Source: Dong Chinese Dictionary