液压泵按工作压力的高低分为低压泵、中压泵、高压泵。
参考答案：错
._______ there is going to be a policy change ________ of those things is going to change. [ ]
A. Unless; few
B. Until; few
C. Unless; none
D. Until; none
盐酸异丙肾上腺素遮光、密封在干燥处保存是为了防止
A．水解B．氧化C．差向异构化D．聚合E．吸收二氧化碳
