通风报信

yào bu shì tā tōng fēng bào xìn wǒ men hái méng zài gǔ li

要不是他通风报信，我们还蒙在鼓里。

Had he not furnished us with the information, we would have still been in the dark.

tōng fēng bào xìn zhī rén

通风报信之人

leaker

qiè zéi dé dào wàng fēng zhě de tōng fēng bào xìn táo pǎo le

窃贼得到望风者的通风报信逃跑了。

The burglars were tipped off by a lookout and escaped.