bolt stay

例句：

1. 1. The bolt on the door was loose and needed to be tightened.
   门上的螺栓松动了，需要拧紧。
2. 2. He used a bolt to hold the door shut.
   他用一个螺栓把门关上。
3. 3. The bolts holding up the roof were rusted and had to be replaced.
   支撑屋顶的螺栓生锈了，必须更换。