vacuum gear shifting

例句：

1. 1. The vacuum gear shifting system isdesigned to improve fuel efficiency.
   真空齿轮换挡系统旨在提高燃油效率。
2. 2. During the shift, the driver must carefully monitor the vacuumgear shifting system.
   换挡期间，驾驶员必须仔细监控真空齿轮换挡系统。
3. 3. Theengineers were tasked with ensuring thatthe vacuum gear shifting mechanism was functioningcorrectly.
   工程师们被指派确保真空齿轮换挡机制正确工作。