Riddle:
一个白球球，两人跟他耍，跑到谁跟前，照头打一下。 （打一体育用品）
The answer is revealed in this text.
桃花溪
唐 张旭
隐隐高桥隔云烟，
石矶西畔问渔船。
桃花尽日随流水，
洞在清溪何处边。
Translation:
A high bridge faintly separates the clouds and mist, questioning the fishing boat on the western shore of the rocks. Peach blossoms flow with the water all day long, where is the entrance of the Peach Blossom Cave?
Notes:
(1) Peach Blossom Creek: The name of a river, located under the Taoyuan Mountain in Taoyuan County, Hunan Province.
(2) Flying Bridge: A high bridge.
(3) Rocky outcrop: Rocks or stone piles protruding from the water or on the water's edge. Fishing boat: From the sentence in Tao Yuanming's "The Peach Blossom Spring".
(4) All day: The entire day, all day long.
(5) Cave: Refers to the entrance of the cave found by the fisherman in "The Peach Blossom Spring".
"Practice what you preach" is from "The Analects of Confucius".
Meaning: Practice what you want to say first, and only say it after you have actually done it.
Riddle Answer: Ping Pong Ball.