1. If you are absent-minded in class, you won't learn anything.2. Sorry, what did you say? I was spaced out for a minute here.3. My friend seems upset and distrait; it turns out his dad is seriously sick.
 Absent-minded be spaced out distrait drift offdrift off 很常用， be spaced out 是俚語，也很常用
1. 上課不專心, 你什麼都學不到.2. 不好意思, 你剛剛說什麼? 我突然恍神了一下.3. 我朋友看起來心不在焉的, 原來是因為他爸病重.
I have been wrecking my brai on this tough math question but I still cannot solve it.