roof-bolt head

例句：

1. 1. The roof-bolt head was damaged during the storm.
   暴风雨期间，屋顶螺栓头部受损。
2. 2. The roof-bolt head is what holds up the roof.
   屋顶螺栓头部是支撑屋顶的关键部分。
3. 3.The roof-bolt head needs to be replaced immediately.
   屋顶螺栓头部需要立即更换。