manual timing

例句：

1. 1. The car's manual timing system is very user-friendly.
   这款车的手动计时系统非常用户友好。
2. 2. The engineer used a manual timing device to check the accuracy of the clock.
   工程师使用手动计时设备来检查时钟的准确性。
3. 3. The manual timing system was used to ensure that the racers were running at the same time.
   手动计时系统被用来确保赛车手们同时起跑。