渔夫在水下安装了发声器来追踪鱼群的位置。

The fishermen installed ___pingers underwater to track the fish schools.

会议室里的手机此起彼伏地响着通知提示音。

All the ___phones in the meeting room kept buzzing with notifications.

运动员们在训练时佩戴追踪器来监测他们的速度和距离。

The athletes wear ___trackers during training to monitor their speed and distance.