每一矿井必须有完整的独立通风系统,其内容包括哪些?
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按照社区治安综合治理方针的要求,基层社区组织要努力抓好哪些方面的工作?
scp保存不保存话单?()
A. 不保存
B. 保存
大型室间隔缺损伴明显肺动脉高压时,出现紫绀,心脏杂音较轻,肺动脉第二音显著亢进。()
A. 正确
B. 错误
To add refrigerant to the low side of an air conditioning system, the refrigerant should be introduced through the ()
A. suction service valve as a vapor
B. suction service valve as a liquid
C. discharge service valve as a vapor
D. charging valve as a liquid