“罄竹难书”应该用在？
When is 罄竹难书 appropriate?
全球翻车率（内测预估）
A形容功劳很大
xíng róng gōng láo hěn dà · describes a great achievement
B形容书很多
xíng róng shū hěn duō · describes having a great many books
✓形容罪行多到写不完（贬义）
xíng róng zuì xíng duō dào xiě bù wán（biǎn yì） · describes crimes too numerous to record (derogatory)
D形容学问深
xíng róng xué wèn shēn · describes deep learning
把竹简用完都写不完的，只能是罪行。拿来夸人，等于当众骂人。
“So many that all the bamboo slips can't record them” — strictly for crimes. Using it as praise is an accidental public insult.