题目内容：
阅读材料，回答题：Computers in Cars
You're far from home on alonely road. Shadowy forests stretch away on both sides. athickmist (雾) makes it difficult to see far beyond your car's windshield (挡风玻璃).
"Can this B．e route 90A?" you wonder. If it is, you should be near atown. Yet there's nohint of one. Night is closing in. And you're low on gasoline.
This is asituation where an in-car computer that can navigate would be abig help.
A car computer that navigates? Yes! Such computers exist. Several experimental models arebeing tested by General Motors, Ford, Chrysler, and several foreign car makers. These computersvary in detail. but they all contain series of maps on videodiscs or videotapes. For example, onecomputer system contains 13,300 maps covering the continental US.
before starting out on atrip, A．driver can type in the code for the region he or she plans todrive through. The computer then shows amap of that region. At the same time, atiny radio re-ceiver linked to the computer goes to work. It picks up signals from navigation satellites such asthe NAVSTAR network. Using these signals, the computer shows the car's position at all timesand displays this position on the map. The computer can also calculate and display the best routeto follow.
Anavigation computer may also receive and use dataabout road construction, weather condi-tions, and trafficjams. This information would be displayed to the driver and the computer wouldalso use the information to work out alternate (交替的 ) routes.
Most cars nowadays also contain computers that help cars run more efficiently. Microproces-sors (微处理的) control certain engine functions B．y regulating the mixing of fuel. Dataon carspeed, oil pressure, revolutions per minute, engine temperature, and fuel level can be displayedas digital data(numbers) or warning lights.
Some auto designers suggest that acentral computer display be used to clearly present suchtimely information as car speed and fuel level. Warning lights would indicate adrop in oil pres-sure or asudden rise in engine temperature. To get more information on these conditions, thedriver could call it up on the computer display screen. When needed, the computer could be"asked" to provide navigation aid or information about the car's condition.
by describing atypical situation of alost driver on the road, the author intends to__________. A．make us believe how complex the highway computer network is
B．let us know how in-car computers are linked to road signs
C．show us how helpful anavigation computer can be
D．tell us that NAVSTAR has come into use
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