Welcome to English in a Minute.
This is a piece of wood. And sometimes we say this: Knock On Wood.
Knock on Wood 老天保佑
Anna: Jonathan, I entered to a contest to win a new car.
Jonathan: Wow, I hope you win!
Anna: Me too, but I have the worst luck in contests. This time, knock on wood, I will win!
Jonathan: Oh, are you okay?
"Knocking on wood" is something people do or say for good luck. People say "Knocking on wood" to mean they need a little luck to help something happen or not to happen. And if there is some wood nearby, you can really knock on it.
And that's English in a Minute!