billiard-marker

例句：

1. 1.The billiards room is always crowded with people playing the game.
   台球室总是挤满了玩这个游戏的人。
2. 2.The cue ball and the ball are marked by the billiard-marker.
   球杆和球被台球标记器标记了。
3. 3.He used to play billiards in his spare time, but now he only plays it for fun.
   他以前在空闲时间打台球，但现在他只是为了好玩才打。