There is a stump (树桩)of a big tree in the state of W ashington. It was oncea "post office". Because people needed a place for the mail carrier(信使) to leavetheir letters, they found a tree at the cross of roads and cut it down ten feet fromthe ground. Then they hollowed it out and covered it with something. Inside, theyput many boxes. Each box had a family's name on it. The mail carrier could leaveletters there for everyone.