The underpart of the plane 's fuselage scraped the treetops .

飞机 机身 的 腹部擦过树顶。

From the change of the voltage of large load underpart judge the technological state of the battery ;

从大负荷 下端电压的变化，判定蓄电池的技术状态；

The underpart of the body of certain vertebrates such as snakes or fish .

某些脊椎动物（像蛇或鱼）身体的 下部。