题干

--- Hello! Is Mr. John in the office?
--- Yes. But I’m sorry. He is busy _________ and can’t speak to you.
A.at onceB.at presentC.at the end D.at first
上一题 下一题 0.64难度 单项选择 更新时间:2012-11-13 07:24:01

答案(点此获取答案解析)