单选题 Scarcely had they settled themselves in their seats in the theatre _____ the curtain went up.无
【正确答案】 C
【答案解析】句意：幕布一拉开， 他们就在戏院里坐下了。 scarcely...when...一……就……， 常用于过去完成时中， 相当于hardly...when...。