[单选] The () compressor and its electrical motor are entirely housed in a gas-tight casing.
A . open-type B . hermetic C . A and B D . None of the above
简述杯体虫病(又称为舌杯虫)的繁殖方式。
調達读音正确的是() ちょうたつ。 ちょうたち。 ちょたつ。 ちょたち。
如何目测判断熔剂?
发行股票是所有公司制企业筹措自有资金的基本方式。()
怎样判断精矿全铁高低?
The () compressor and its electrical motor are entirely housed in a gas-tight casing.