为防止高流风机风机烧皮带烧毁，甚至烧毁电机，启动前管路各阀门应在什么位置？
参考答案：
开启状态
The young man helped the company recover , so his boss gave him an apartment ____.
A．in return
B．in turn
C．in charge
D．in fact
高频铸造机的工作原理是
A．熔焊B．电阻焊C．电流感应加热D．离心E．涡流
