下列物质中属于有毒物质的是（）
A.氯化钡
B.氯气
C.甲醇
D.氯化钠
参考答案：A, B, C
no modern telecommunications, we would have to wait for weeks to get news from around the world.
A．Were there
B．Had there been
C．If there are
D．If there have been
《电子式电流互感器技术规范》规定，220kV电子式电流互感器二次保护用数字量输出的额定值（）为（）。
