三鹿奶粉出现加入三聚氢铵事故后，伊利、蒙牛、光明等乳业巨头共损失43.68亿元，用科学记数法记为_______________元.

In most wide area networks, the communication subnet consists of two distinct components：transmission lines and

A． networts

B． switching elements

C． computers

D． data terminal equipment