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：
When it came to cleaning up afterwards, Anne was conspicuous by her absence.
后来到做扫除时，本应在场的安妮却因为不在而引起了注意。
His absence went unremarked.
没有人注意到他不在场。
There is more to good health than the mere absence of disease
身体健康不仅仅指不生病，还包括更多。
The presence or absence of clouds can have an important impact on heat transfer
有无云层对热量的`传递会产生重要的影响。
The official reason given for the President's absence was sickness.
对外公布的总统未到场原因是身体有恙。
