Today's Phrase.

A busy man is a happy man.

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Very busy bees.

Bees' wings move very fast. They move them up and down around 200 times a second.

Bees look like very busy animals, so if you say you are as busy as a bee, or call yourself a busy bee it means you're very busy!

Examples:

I've been a really busy bee this morning. I've been to the shops, paid my bills, had a haircut and even been for a run.

Frank is such a busy bee. He's always doing about five projects at once! He needs to take it easy.

If you have a bee in your bonnet about something, it means you are obsessed by that thing - you can't stop thinking about it.

Example:

He's got a bee in his bonnet about fast cars. He talks about them all day long!

Go under the knife.

Surgeons performing an operation

Human beings have been using knives for at least 2.5 million years. They were originally made from rock, bone and flint.

Examples:

England's best footballer won't play at the World Cup. He's going under the knife and won't recover in time for the start of the tournament.

I had tonsillitis eight times before doctors decided that I needed to go under the knife and have my tonsils removed.

Don't confuse this expression with put to the sword. That phrase means to kill something.

Example:

The captured soldiers should have been kept in a military prison but instead they were put to the sword. Hundreds were killed.

( Nguồn : BBC Learning English )