semi-drop center rim

例句：

1. 1. The car's engine is asemi-drop center, which makes iteasy to start and stop.
   这辆车的引擎是半滴中心，这使得它容易启动和停止。
2. 2. The design of the newphone has a semi-drop centerthat makes it more comfortable to hold.
   这款新手机的设计有一个半滴中心，使得握持起来更加舒适。
3. 3. The artistused a semi-drop center technique tocreate this painting.
   这位艺术家使用了半滴中心技术来创作这幅画。