视频对白：
Traffic copters were out in force that day but only one caught all action from the beginning to end, channel 12.
交通直升飞机正在巡逻，但是只有一架从头到尾拍下了全过程，那就是12频道的直升飞机。

今天要学习的词组为：in force

意为：“有效的；大批地；大规模地”。

例句：
1. Strict rationing of basic foodstuffs was still in force by the end of the year.
到年底还在实施严格的基本粮食配给。

2. In the teak - bearing districts the old compulsory services remained in force.
在柚木产区仍然保留了旧的强迫劳役制。