药物结合的主要作用位点（）
A.血浆白蛋白
B.红细胞
C.脂蛋白
D.球蛋白
E.补体
参考答案：A
Our teacher told us last night that ___.
A．English is difficult to be learnt
B．the English is difficult to learn
C．the English language is difficult to learn
D．English language is difficult to learn
当电力线路、电气设备发生火灾时应立即断开（）。
A.电压
B.电流
C.电源
D.电阻
