gǎn jī bù jìn
can't thank sb enough (idiom)
shū bù jìn yán
I have much more to say than can be written in this letter (conventional letter ending) (idiom)
qǔ zhī bù jìn , yòng zhī bù jié
limitless supply (of)
inexhaustible
zhī wú bù yán , yán wú bù jìn
not hiding anything he knows, not stopping before he has said it through (idiom)
frank
outspoken
yán bù jìn yì
(conventional letter ending) words cannot fully express what is in my heart (idiom)