头脑

She has plenty of brains.

His head seems completely empty/vacant.

All that praise has really gone to his head.

Keep your wits about you when you are driving.

Reading enriches the mind.

be in one's right mind/head

keep a clear/cool head; be sober-minded/clear-headed

have a quick/sharp/nimble/keen mind

have quick/ready/nimble wits; have an active brain

be sober-minded/level-headed/cool-headed; have a cool head

have an empty skull; have a vacant mind

be simple-minded; see things too simply

become hot-headed

feel giddy/dizzy; one's head swims/reels

have a brilliant mind

be slow-minded; be weak of brain; have slow wits; obtuse; dull-witted

have a closed mind

have a head for mathematics

be commercially/politically minded

have a scientific mind

fill one's head with knowledge

not use one's head

I cannot make head or tail of these instructions.