"let alone" or "not to mention" are often just filler. "not to mention" can sometimes be used to good effect because of its irony: whenever you say "not to ... ... <看更多>

not to mention 和let alone 都是更不用說的意思我查到一個句子是He can't speak English,let alone Italian. 他不會說英文,更別說是義大利文了請問 ... ... <看更多>

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4. let alone / not to mention (遑論) - to say nothing of; not to speak of; used especially to emphasize the improbability of a contrasting example; ... ... <看更多>