spiro compound

例句：

1. 1. The spiral staircase leads up to the second floor.
   螺旋楼梯通向二楼。
2. 2. The helix of the screw is the curved part that turns the screw.
   螺丝的螺旋部分是使螺丝转动的弯曲部分。
3. 3. The coiled spring was released and began to unwind.
   卷曲的弹簧被释放并开始放松。