cue

老师给了我一个提示，让我开始发言。

The teacher gave me a ___cue to start speaking.

他把台球杆放在台球桌旁边的架子上。

He placed the ___cue on the rack beside the pool table.

老师的手势是学生们开始讨论的提示。

The teacher's hand gesture served as a ___cue for the students to start discussing.