分子筛纯化系统的再生时间由()、加温、()、升压四部组成。
参考答案:降压;吹冷
Scientists say they have found a way to produce the human body’s own cancer-killing cells through gene treatment, ______ new hope to cancer sufferers.
A.offering
B.showing
C.taking
D.making
负逻辑体制中用O表示()
A、电压为0伏
B、低电平
C、高电平
D、断路