封闭式

The amphitheater was a sealed off round structure. Swordplay, wresting, gladiatoral and other contests were held there.

该竞技场为四周结构，可举行斗剑、格斗、斗兽及其他竞赛项目。

Silicon Electable Stove are heating instruments often used by factory mines,enterprises,hospitals,college labs.It has tno styles:Openingclosing.

电炉为工矿、企业、医院、大中院校实验室常用的加热设备，分为开和两种。

Bench of closed circuit cooling tower that is composed of boiler ,exchanger, orifice flowmeter, water pump, micromanometer , heat indicator and so on is established.

建立了由锅炉、换热器、孔板流量计、水泵、微压计、温度计等仪器设备组成的冷却塔实验台。