An internet is a combination of networks connected by （） . When a datagram goes from a source to a （） , it will probably pass many （） until it reaches the router attached to the destination network. A router receives a （） from a network and passes it to another network. A router is usually attached to several networks. When it receives a packet, to which network should it pass the packet The decision is based on optimization: Which of the available （） is the optimum pathway

it will probably pass many （） until it reaches the router attached to the destination network.

A．destinations 

B．routers 

C．packets 

D．computers

下列关于计算机的叙述中，不正确的一条是

A．运算器主要由一个加法器、一个寄存器和控制线路组成

B．一个字节等于8个二进制位

C．CPU是计算机的核心部件

D．磁盘存储器是一种输出设备