题目内容：
Computers in Cars You ’re far from home 0n a lonely road．Shadowy forests stretch away 0n both sides．A thick mist （雾）makes it difficult to see far beyond your car’s windshield（挡风玻璃）．“Can this be route 90A? ” you wonder． If it is，you should be near a town． Yet there’s no hint of one． Night is closing in． and you’re low on gaso1ine．
This is a situation where an in-car computer that can navigate Would be a big help．
A car computer that navigates? Yes! Such computers exists． Several experimental models are being tested by General Motors，Ford，Chrysler，and several foreign car markets．These computers vary in details． But they a11 contain series 0f maps on Vediodiscs or videotapes． For example，one computer system contains 1 3，300 maps covering the Continental US．
Before starting out 0n a trip，a driver can type in the code for the region he 0r she plans to drive though．The computer then shows a map 0f that region． At the same time， a tiny radio receiver linked to the computer goes to work． It picks up signals from navigation satellites such as the NAVSTAR network． Using these signals， the computer shows a the car’s position at all times and displays this position on the map． The computer can also calculate and display the best route to follow．
A navigation computer may also receive and use data about road construction． weather conditions，and traffic jams． This information would be displayed to the driver and the computer would also use the information to work out alternate（交替的）routes．
Most ears nowadays also contain computers that help cars run more efficiently． Microprocessors （微处理机的）Control certain engine functions by regulating the mixing of fuel．Data on car speed， oil pressure，revolutions per minute， engine temperature， and fuel level can be displayed as digital data（numbers）or warming lights．
Some auto designers suggest that a central computer display can he used to clearly present such timely information as ear speed and fuel level． Warning 1ights would indicate a drop in oil pressure or a sudden rise in engine temperature． To get more information 0n these conditions， the driver would call it up on the computer display screen． When needed，the computer could he “asked” to provide navigation aid or information about the car’s Condition．By describing a typical situation of a lost driver on the road，the author intend to A．make us believe how complex the highway computer network i
C．let us know how in-ca computers are linked to road signs
D．show us how helpful a navigation computer would be
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