单选题 I greatly/regret that I'm unable to attend the important sales meeting next Monday.

【正确答案】 D
【答案解析】[分析] 注意regret意为“遗憾”,短语attend the important sales meeting next Monday中next Monday作定语修饰meeting,attend意为“出席(会议)”,整个短语译为“出席下周一那个重要的销售会议”。