absence of mind
1. 心不在焉
He failed in the exam because of his absence of mind.
他因心不在焉而考试不及格。
习惯用语A-makes the heart fonder.1.■[谚]眼不见, 心更念; 别久情深。conspicuous by one's absence1.■因缺席而引人注目; 因缺少...而受人注意in the absence of1.■缺乏...时; 当...不在时leave of absence1.■请假, 准假absence of mind1.■精神不集中; 心不在焉2.■擅离职守;【军】开小差