缺席的短语：be absent from

例句：You should not be absent from school without cause.

没有理由，你不该缺席。

absence

n.

1. 不在,缺席[U][C][(+from)]

She never speaks ill of anyone in his or her absence.

她从不乘人不在时说别人的坏话。

2. 缺少,缺乏[U][(+of)]

The absence of color in that drawing makes it dull.

那幅画因没有着色而显得晦暗属。