absence 接介词 from表示“离开某地,不在某地”; 接介词 at 或 in表示“不在某地而在他处”; 接介词of表示某人、某物或者某事物“缺乏”或者“不存在”。而in absence意为“在缺乏或不存在的情况下”; in sb's absence意为“当某人不在时,在某人离开时”; in the absence of则意为“在缺少…时”。
例句：
She concocted some elaborate story to explain her absence.
她精心编造了解释她不在场的一些谎言。
The case was dismissed in the absence of any definite proof.
此案因缺乏确凿证据而不予受理。
She took advantage of the children's absence to tidy their rooms.
她趁孩子们不在时收拾了他们的房间。