主变中性点装设放电间隙保护的作用？
参考答案：
保护变压器中性点绝缘。
麻疹的传播途径是（）
A.性传播
B.接触传播
C.母婴传播
D.飞沫传播
E.血液传播
(66) is defined as the buying and selling of products and services over the Internet. It had included the handling of purchase (67) and funds transfers over computer networks from its inception.
A．jobs
B．transactions
C．programs
D．files
