制冷系统中压缩机吸入的是下列哪一种状态的制冷剂（）
A.常温低压液体
B.低温低压液体
C.常温低压气体
D.低温高压气体
参考答案：C
_______he was laid off last year ______ how serious the economic crisis was.
A．Not until…he realized
B． It was not until… when he realized
C．It is not until…that did he realize
D．It was not until …that he realized
油品罐的安全附件主要有( )、阻火器、放水阀、排污阀。
A．安全阀B．呼吸阀C．泄压阀D．报警器
