spiral micrometer

例句：

1. 1.The spiral staircase leads up to the second floor.
   螺旋楼梯通向二楼。
2. 2. The spider spins a web with its long legs.
   蜘蛛用长腿编织一张网。
3. 3. The car's engine is designed to spin smoothly.
   汽车发动机设计得能平稳旋转。