absent-minded
adj. 健忘的,心不在焉的
Someone who is absent-minded forgets things or does not pay attention to what they are doing, often because they are thinking about something else.
In his later life he became even more absent-minded.
他晚年變得愈加健忘了。
He's very learned but rather absent minded.
他很有學問,可是好忘事.
The absent minded representative presented a present to me.
心不在焉的代表給我送了一份禮物.