老底

tā de lǎo dǐ bèi jiē chuān hòu bù dé bù lí kāi zhè ge guó jiā

她的老底被揭穿后不得不离开这个国家。

She had to leave the country after her cover was blown.

nǐ chà diǎn jiē le wǒ men de lǎo dǐ

你差点揭了我们的老底。

You almost biew our cover.

tā rèn wéi tā yǐ jīng mō qīng tā de lǎo dǐ le

她认为她已经摸清他的老底了。

She thinks she's got him taped.

tā jiā de lǎo dǐ hòu

他家的老底厚。

His family is rather wealthy.

jī nián gōng fu tā jiù bǎ lǎo dǐ bài guāng le

几年工夫他就把老底败光了。

In a few years' time, he had frittered away his inheritance.