发令枪

例句：

1. 1. The racers lined up at the starting line withtheir sprinting guns ready tofire.
   赛跑者在起跑线排队，他们的短跑枪已经准备好发射。
2. 2. The coach gave the signal with hiswhistle, and the players fired their gunsin unison.
   教练用哨子发出信号，球员们同时开枪。
3. 3. Theathletes lined up at thestarting gate, each holding agun that would shoot them forward.
   运动员们站在起跑线上，每人都拿着一个会射出的枪。