在空分装置中,蒸汽冷凝和液体蒸发的过程是两个相反的过程,但都是()
A.质到量变
B.质到质变
C.量到质变
参考答案:C
Mr. Liu dreamed ____ a big house for his parents after they retire.
A.to buy
B.to buying
C.of buying
D.of being buying
突发公共卫生事件中预防接种和预防服药群体性不良反应事件的报告范围?