注射于靶区内动脉末端（）
A.静脉注射
B.皮内注射
C.动脉内注射
D.脊椎腔注射
E.皮下注射
参考答案：C
One of the most important questions they had to consider was ______ of public health.
A．what
B．this
C．which
D．that
氢离子浓度对反应速率常数测定是否有影响？
