If you find yourself needing to do this, consider whether a tree control or other element better suited to multiple-level hierarchies would be more appropriate.
如果你发现需要这样做，树状菜单或者其他的适合显示多级结构的元素可能更合适。
2
The permission propagation constraint improves the access control grain. It makes the grain reach element or attribute level.
权限传递约束提高了访问控制的粒度，使得访问控制的粒度能够达到元素或属性级。
3
The control characteristics of low light level 61 element adaptive optical system are analyzed based on an one order proportional integral controller.