Sometimes, American English does not make any sense. Like if someone says this: You can't squeeze blood out of turnip.
Vegetables don't have any blood in them...And who is squeezing turnips?
Let's see if we can figure out what it means...
A: Hey, Can you loan me $50.00, I can pay you back on Friday.
B: I wish I could help, but I don't have any money....
A: Are you sure? I really need it.
B: I understand, but you can't squeeze blood out of turnip.
You can't squeeze blood from a turnip means you cannot get something from a person that they don't have to give you. And it's used about money.
You see, it actually makes sense, because no matter how hard you squeeze a turnip, it will never bleed, and if somebody does not have any money to give you, you'll never be able to get it.
And that's English in a Minute.