preformed

Dacryocystography was preformed in all patients before operation to confirm the obstructive sity and the size of lacrimal sac.

术前造影以了解泪囊大小和阻塞部位，以选择最佳手术适应证。

When installation, unlade the join copper bus bar, through the preformed long-square hole, fixing it on the main grounding bus bar.

安装时将互连铜排卸下，穿柜间留长方孔，固定在相邻两柜主接地铜排上。