If you have a bee in your bonnet about something, you are obsessed with it and can't stop thinking about it. This phrase is often used when you are worried or angry about something. The word 'bonnet' refers to a kind of hat.
The council wants to close down our local library. I've got a bee in my bonnet about it!
Mum's got such a bee in her bonnet about the wedding. I keep telling her that it will be fine, but she's very worried.
If something or someone is the bee's knees, they are very good.
Darren bought me a new car for my birthday - he's the bee's knees.
There are over 60,000 bees in the average bee colony. A honey bee can fly up to 8km per hour, beating its wings approximately 200 times per second.