A movie actor will sometimes have a fight in which he breaks a chair over another man's head. How does he do it without injuring the other actor? The trick is to use a chair made of very light wood. A chair made of balsa wood is very light. If you're hit with a balsa wood chair you won't be injured.

一个电影演员有时要打斗，打斗过程中他会在另一个人的头上打碎把椅子。他要怎样做才不会伤到另一个演员？窍门是使用很轻的木头制成的椅子。一个用软木制成的椅子非常轻，如果你被这种轻木椅子砸上了，你是不会受伤的。