movable eyepiece

例句：

1. 1.The chair is movable, so it can be moved around the room.
   椅子是可移动的，所以可以移到房间的任何地方。
2. 2. The movable parts of the machine are easy to fix.
   机器的可移动部件很容易修理。
3. 3.The movable seat on the train allows passengers to sit in different positions.
   火车上的可移动座位允许乘客坐在不同的位置。