bù yòng zhǎo
"keep the change" (restaurant expression)
bù yòng kè qi
You're welcome (that is, please don't thank me)
There is no need to stand on ceremonies.
wú suǒ bù yòng qí jí
committing all manner of crimes
completely unscrupulous
bù yòng xiè
You're welcome
Don't mention it
bèi ér bù yòng
have sth ready just in case
keep sth for possible future use
zhòng fá bù yòng
do not punish severely (and do not reward too generously)