- Rack one`s brain:
To try hard to think of something or remember something.
e.g. I racked my brain to try and decide what to do about the computer problem.
- Beat one’s brain out (to do something):
To try very hard to to do something.
e.g. If you think I’m going to beat my brains out to do this, you are crazy.
I beat out my brains to do this for you!
I won’t beat my brains out again for you!
- Ain’t got the brains God gave a squirrel and ain’t got the sense God gave geese:
Is or are very foolish.
e.g. There goes John, running around barefooted in the snow. He ain’t got the brains God gave a squirrel.
No use trying to explain anything to Jane. She ain’t got the sense God gave geese.
- Pick the brains of (someone) or pick (someone’s) brains:
To talk to someone in order to get some information about something.
We picked the brains of the official who was talking about the pollution problem.