lever bracket bolt and nut

例句：

1. 1.The lever is used to lift heavy objects.
   这个杠杆用来举起重物。
2. 2. The bolt was too tight to be removed without tools.
   这个螺栓太紧了，没有工具无法拆卸。
3. 3.The nuts were loosened by the force of the turning bolt.
   螺栓转动的力量使螺母松动。