fulcrum

例句：

1. 1. The fulcrum of the lever is at its middle.
   杠杆的支点位于其中间。
2. 2. The fulcrum of the balance is on the edge of the scales.
   天平的支点位于秤的边缘。
3. 3. The fulcrum of the swinging door is the hinge.
   摇摆门的支点是铰链。