碳素钢按质量分类有()碳素钢,()碳素钢,()碳素钢。
参考答案:普通;优质;高级优质
Modern science has given clear evidence _____ smoking can lead to many diseases.[ ]
A. what
B. which
C. that
D. where
关于CO2排出综合征的临床特点,下列不正确的是
A.其表现为血压下降、心动过速、严重心律失常甚至心脏停搏B.治疗时不必补充血容量C.CO2突然排出可使冠脉和脑血管收缩D.PaCO2持续升高一段时间后突然降低可诱发此症E.治疗PaCO2升高,通气量要逐步增加