—Sorry indeed, I ________ to your birthday party if …

—Forget it. I know you were out on business.

A．must come

B．would come

C．must have come

D．would have come

A local-area network (LAN) is a communications network that (125) a variety of devices and provides a (126) for information exchange among those devices. The scope of the LAN is small typically a single building or a cluster (丛) of buildings. The LAN is usually owned by the same organization that owns the (127) devices. The internal data rate of LAN is at least several Mb/s.

The basic of LAN communication is broadcasting. At each station, there is a transmitter/receiver that communicates over a (128) shared, By other stations. A transmission from any one station is (129) to and received by all other stations.

（129）是（）

A.broadcast

B.cable

C.control

D.interconnects

E.internet

F.meander

G.means

H.medium

I.modem

J.output switch relay