他真是个健忘的人，连自己把钥匙放在哪儿都记不住。

He's such a ___scatterbrain that he can't even remember where he put his keys.

我最近睡眠不足，工作时感觉完全心不在焉。

I've been sleep-deprived lately and feel like a total ___scatterbrain at work.