Driving needs sharp eyes,keen ears,quick brain,and coordination（协调）between hands and the brain.Many human drivers have all（51）and can control a fast-moving car.But how does an intelligent car control itself?

There is a virtual（虚拟的）driver in the smart car.This virtual driver has"eyes,""brains,""hands"and"feet,"too.The minicameras（52）each side of the car are his"eyes,"which（53）the road conditions ahead of it.They watch the（54）to the car's left and right.There is also a highly automatic driving（55）in the car.It is the built-in computer,which is the virtual driver's"brain."His"brain"（56）the speeds of other moving cars near it and analyzes their positions.Basing on this information,it chooses the（57）path for the intelligent car,and gives instructions to the "hands"and"feet"to act accordingly.In this way,the virtual driver（58）his car.

What is the virtual driver's best advantage?He reacts（59）.The minicameras are bringing（60）continuously to the "brain."It completes the processing of the images within 100 milliseconds.（61）,the world's best driver needs at least one second to react.Besides,when he takes（62）,he needs one more second.

The virtual driver is really wonderful.He can reduce the accident（63）considerably on expressways（高速公路）.In this（64）,can we let him have the wheel at any time and in any place?Experts（65）that we cannot do that just yet.His ability to recognize things is still limited.He can now only drive an intelligent car on expressways.

51.A.these　B.them　C.this　D.that

52.A.in　B.above　C.to　D.on

53.A.change　B.observe　C.improve　D.meet

54.A.police　B.traffic　C.pets　D.trees

55.A.button　B.door　C.system　D.activity

56.A.calculates　B.reaches　C.gathers　D.reduces

57.A.different　B.narrow　C.same　D.right

58.A.stops　B.finds　C.controls　D.selects

59.A.quickly　B.cleverly　C.virtually　D.safely

60.A.ideas　B.news　C.memory　D.images

61.A.so　B.However　C.Besides　D.Therefore

62.A.action　B.role　C.decision　D.notice

63.A.investigation　B.prevention　C.rate　D.report

64.A.case　B.method　C.manner　D.file

65.A.expose　B.warn　C.hope　D.wish