如果你想知道一个秘密，敲三下门。

If you want to know a secret, knock three times.

youdao

割完草之后，她用刀柄在地上敲三下，小手便又从土地里露出来。

When the turf was all cut, they saw her make three taps on the ground with the handle.

youdao

在我洗衣服的时候，时钟敲三下，我立刻停下手中的活，去看世界杯的电视转播了。

I was washing, when the clock striked three I immediately stopped to watching World Cup 2006 on TV.

youdao