In (66) the strength of the carrier signal is varied to represent binary 1 or 0. (67) is a system that can map a name to an address and conversely an address to al name. (68) is a three-way handshaking authentication protocol that it’s packets are encapsulated in the point-to-point protocol. (69) is an approach that enables an ATM switch to behave like a LAN switch. (70) is an guided media which is made of glass or plastic and transmits signals in the form of light.

A．NAT

B．NCP

C．DDN

D．DNS

关于常用制药用水的错误表述是（）。

A.纯化水为原水经蒸馏、离子交换、反渗透等适宜方法制得的制药用水 

B.纯化水中不含有任何附加剂 

C.注射用水为纯化水经蒸馏所得的水 

D.注射用水可用于注射用灭菌粉末的溶剂 

E.纯化水可作为配制普通药物制剂的溶剂