keep it down 安静一些，小声一点

Hey you guys, keep it down in there – I’m on the phone!

嗨，你们小点声，我在打电话!

A: I hate to bring this up, but that new stereo system you got. . .

我本不想提的，只是你新买的音响……

B:What's the matter?

怎么啦?

A: You were playing it very late last night. It kept me awake.

你昨晚一直放到很晚。吵得我都没睡着。

B: I'm awfully sorry. I didn't realize it. I promise I'll keep it down in the future.

很对不起，我当时确实没意识到会有那么大声。我保证以后把声音开小些。