言大人有所不知
“You may not know this, Lord Yan,”
THE DIALOGUE REEL
言大人
“Lord Yan.”
言大人 有所不知
“You may not know this, Lord Yan,”
八爷 已被除族 且钉齿铭誓 不再制墨
“but he has been expelled from the clan and has sworn a solemn oath, sealed with the nailing of a tooth, never to make ink again.”
“You do not know the full picture, so allow me to explain the reality.”
In traditional hierarchical discourse, directly contradicting an official is taboo, so speakers preface corrections with deferential formulas like 'you might not know'.
LEARNING CHUNKS & PARTICLES
there is something one does not know
A polite, classical idiom used before explaining an unfamiliar circumstance to someone, especially a superior or guest.