Ⅰ. excuse … for “原谅某事”。如：
① He excused me for being late. 他原谅我迟到了。
② Please excuse me for using your telephone without asking permission. 请原谅我没经你允许就用了你的电话。
Ⅱ. excuse … from “使免于……，允许不……”如：
① The teacher excused him from the examination. 教师同意他免试。
② The boy was excused from doing housework. 允许这男孩不做家务事。