three stub tuner

例句：

1. 1. We need to tune the car's radio to the correct frequency for the trip.
   我们需要把汽车的收音机调到正确的频率，以便这次旅行。
2. 2. The three-battery tuner is a handy tool for musicians who want to keep their instruments in tune.
   三个电池调音器是音乐家们保持乐器调音的好帮手。
3. 3. The three-battery tuner was designed to make it easier for people to tune their guitars and other stringed instruments.
   三个电池调音器的设计是为了使人们更容易地调整他们的吉他和其他弦乐器。