while there ilife, there ihope.以下是小编为大家搜索整理的专四英语考前指导完形填空练习题，希望能给大家带来帮助!更多精彩内容请及时关注我们应届毕业生考试网!
Flight simulator (飞行模拟器) refers to any electronic or mechanical system for trainingairplane and spacecraft pilots and crew member by simulating flight conditions. The purpose ofsimulation is not to completely substitute (1)_____ actual flight training but to thoroughlyfamiliarize students with the vehicle (2)_____ before they (3)_____ extensive and possiblydangerous actual flight training. Simulations also is useful for review and for familiarizing pilotswith new (4)_____ to existing craft.
Two early flight simulators appeared in England within a decade after the first flight of Orvilleand Wilbur Wright. They were designed to enable pilots to stimulate simple aircraft (5)_____in three dimensions： nose up or down; left wing high and right low， or vice versa; and (6)_____ to left or right. It took until 1929， however， for a truly effective simulator， the LinkTrainer， to appear， devised by Edwin A. Link， a self-educated aviator and inventor fromBinghamton， New York. (7)_____， airplane instrumentation had been developedsufficiently to permit “blind” flying on instruments alone， but training pilots to do so involved(8)_____ risk. Link built a model of an airplane cockpit equipped (9)_____ instrumentpanel and controls that could realistically stimulate all the movements of an airplane. Pilots coulduse the device for instrument training， manipulating the controls (10)_____ instrumentreadings so as to maintain straight and level flight or (11)_____ climb or descent with no visualreference (12)_____ any horizon except for the artificial one on the instrument panel. Thetrainer was modified (13)_____ aircraft technology advanced. Commercial airlines began touse the Link Trainer for pilot training， and the US government began purchasing them in 1934， (14)_____ thousands more as World War II approached.
Technological advances during the war， particularly in electronics， helped to make theflight simulator increasingly (15)_____. The use of efficient analog computers in the early1950s led to further improvements. Airplane cockpits， controls， and instrument displays hadby then become so individualized that it was no longer feasible to use a generalized trainer toprepare pilots to fly anything (16)_____ the simplest light planes. By the 1950s， the US AirForce was using simulators that precisely (17)_____ the cockpits of its planes. During theearly 1960s (18)_____ digital and hybrid computers were adopted， and their speed andflexibility revolutionized simulation systems. Further advances in computer and (19)_____technology， notably the development of virtual-reality simulation， have made it possible to(20)_____ highly complex real-life conditions.
1. A. for B. to C. with D. on
2. A. concerning B. concern C. being concerned D. concerned
3. A. undertake B. undergo C. underplay D. underuse
4. A. models B. modifications C. modifiers D. modica
5. A. manifestations B. manipulations C. manifestoes D. maneuvers
6. A. yawling B. yawning C. yawing D. yawping
7. A. From then on B. From now on C. By now D. By then
8. A. considerable B. considerate C. considering D. considered
9. A. for B. in C. with D. on
10. A. on the part of B. on the basis of C. on the track of D. on the verge of
11. A. control B. controllable C. controlled D. controller
12. A. to B. for C. on D. in
13. A. as for B. as to C. as D. for
14. A. acquiring B. requiring C. sustaining D. retaining
15. A. actual B. realistic C. realizing D. true
16. A. except B. except for C. apart from D. but
17. A. replenished B. replaced C. replicated D. reposed
18. A. electronic B. electric C. electricity D. electron
19. A. program B. programmable C. programmed D. programming
20. A. resurrect B. reproduce C. resuscitate D. resume
参考答案：1-5： A D B B D 6-10： C D A C B
11-15：C A C A B 16-20：D C A D B
