新东方在线：考研英语核心词汇3

考研网

absence of mind心不在焉
    同义替换：
    being absent-minded
    absence 原始涵义：
    n. 缺席，不在 I want to ask for leave of absence for several days. 我想请几天假。
    缺乏，不存在 In the absence of anybody more experienced, I took command. 由于找不到其他更有经验的人，只好由我来指挥。
    造句：
    Frequently absence of mind in the class made him fail in the exam.
    经常在课上心不在焉使他考试不及格。