老本

kuī lǎo běn

亏老本

lose one's capital

lāo huí lǎo běn

捞回老本

win back one's lost money

shū guāng lǎo běn

输光老本

lose one's last stakes

wǒ gōng zuò kào xué xiào nà diǎn lǎo běn

我工作靠学校那点老本。

The bit of knowledge I've been using was obtained while I was at school.

wàng le lǎo běn

忘了老本

forget the original basis