单选题 23.______dull he may be, he is certainly a very successful top executive.
【正确答案】 D
【答案解析】此句考查连词的用法。although虽然,尽管,引导让步状语从句;whatever无论怎样的,引导名词从句;as引导让步状语从句;however无论如何,引导让步状语从句,从句需要部分倒装。答案是D。