TOEFL全真試題(5

1、TOEFL全真試題（5Albert Ein stein was the first to suggest the existe neeof stimulated emissi on in apaper published in 1917. However , for many years physicists thought that atoms andmolecules always were much more likely to emit light spontan eously and that stimulatedemission thus always would be much

2、weaker. It was not un til after the Second WorldWar that physicists began trying to make stimulated emissi on domi nate. They soughtways by which one atom or molecule could stimulate many other to emit light ,amplifyi ng it to much higher powers.The first to succeed was Charles H.Townes, then atColo

3、mbia Un iversity in NewYork .In stead of work ing with light , however, he workedwith microwaves, which havea much Ion ger wavele ngth, and built a device he called amaser for MicrowaveiAmplificati on by the Stimulated Emissi on of Radiati on. Although he thought of thekey idea in 1951, the first ma

4、ser was not completed un til acouple of years later. Beforelong, many other physicists were buildingmasers andtrying to discover how to producestimulated emissi on at eve n shorter wavele ngth.The key con cepts emerged about 1957. Townes andArthur Schawlow, then at BellTelepho ne Laboratories, wrote

5、 a long paper outl ining thecon diti ons n eeded to amplifystimulated emission of visible light waves. At about the same time, similar ideascrystallized in the mind of Gordon Gould, then a 37- year-old graduate stude nt atColumbia, who wrote them dow n in a series of no tebooks.Townes and Schawlowpu

6、blished their ideas in a scientificjournal, PhysicalReview Letter, but Gould filed apate nt applicati on. Three decades later, people still argueabout who deserves the creditfor the con cept of the laser.1. The word co in in line 1 could be replaced by(A) created(B) men ti oned(C) un derstood(D) dis

7、covered2. The word in terve ntio n in line 4 can best be replacedby(A) n eed(B) device(C) in flue nee(D) source3. The word it in line 5 refers to(A) light bulb(B) en ergy(C) molecule(D) atom4. Which of the following statements best describes a laser?(A) A device for stimulati ng atoms and molecules

8、to emitlight(B) An atom in a high-e nergy state(C) A tech nique for destro ying atoms or molecules(D) An in strume nt for measuri ng light waves5. Why was Tow nes early work with stimulated emissi on done with microwaves?(A) He was n ot concerned with light amplificati on(B) It was easier to work wi

9、th Ion ger wavele ngths.(C) His part ner Schawlow had already beg un work on the laser.(D) The laser had already bee n developed6. In his research at Columbia Uni versity, Charles Townes worked with all of the followi ng EXCEPT(A) stimulated emissi on(B) microwaves(C) light amplificatio n(D) a maser

10、7n approximately what year was the first maser built?(A) 1917(B) 1951(C) 1953(D) 19578. The word emerged in line 20 is closest in mea ning to(A) in creased(B) con eluded(C) succeeded(D) appeared9. The word outl ining in line 21 is closest in meaning to(A) assig ning(B) study ing(C) check ing(D) summ

11、ariz ing10. Why do people still argue about who deserves the credit for the con cept of the laser?(A) The researchers no tebooks were lost.(B) Several people were develop ing the idea at the sametime.(C) No one claimed credit for the developmentuntilrece ntly.(D) The work is still in complete.Questi

12、on 11-21Panel painting,com monin thirtee nth-andfourtee nth -ce ntury Europe , i nv olved apainstaking, laborious process. Wooden planks werejoin ed, covered with gesso toprepare the surface for painting , and then polishedsmooth with special tools. On thisperfect surface, the artist would sketch a

13、compositi on withchalk, refine it with in ks,and the n beg in the deliberate process of appl ying thin layers of egg tempera paint (eggyolk in which pigme nts are suspe nded) with small brushes.The successive layeri ng ofthese meticulously applied paints produced the fin al, tran sluce nt colors.Bac

14、kgro unds of gold were made by carefully appl yingsheets of gold leaf, and the nembellishi ng of decorat ingthe gold leaf by pun chi ngitwith a metal rod on which apatter n had bee n embossed. Every step in the process wasslow and deliberate . Thequick-dryingtempera demanded that the artist knowexac

15、tly where each stroke beplaced before the brush met the pan el, and it required theuse of fine brushes. It was,therefore , an ideal technique for emphasizing the hard lin ear edges and pure, fine areasof color that were so much a part of the overall aestheticof the time. The no ti on that anartist c

16、ould or would dash off an idea in a fit of spontan eous in spirati on wascompletely alie n to these deliberately produced works.Furthermore,mak ingthese paintings was sotime-c onsuming that it dema ndedassista nee. All such work was done by collective en terprisein the workshops. Thepain ter or mast

17、er who is credited with hav ing created pain ti ng may have desig nedthe work and overseen its production, but it is highly un likely that the artists handapplied every stroke ofthe brush. More likely, numerous assista nts, who had bee ntrained to imitate the artists style, applied the paint. Thecar

18、pe nters shop probablyprovided the frame and perhaps supplied the pan el, andyet ano ther shop supplied thegold. Thus, not only many hands , but also many shops were invo Ived in the finalproduct.In spite of problems with their con diti on, restorati on,and preservati on many panelpaintings have sur

19、vived, and today many of them are housed in museum collecti ons.11. What aspect of panel paintings does the passage mainly discuss?(A) Famous examples(B) Differe nt styles(C) Restorati on(D) Production12. Accord ing to the passage, what does the first step inmaking a panel pain ti ng ?(A) Mixi ng th

20、e pai nt(B) Prepari ng the panel(C) Buyi ng the gold leaf(D) Maki ng ink draw ings13. The word it in line 4 refers to .(A) chalk(B) compositi on(C) artist(D) surface14. The word deliberate in line 5 is closest in meaning to(A) decisive(B) careful(C) natural(D) unu sual15. Which of the following proc

21、esses produced the translucent colors found on panel paintings? (A) Joining woode n pla nks to form large sheets(B) Polishi ng the gesso(C) Appl ying many layers of paint(D) Coveri ng the backgr ound with gold leaf16. What characteristic of tempera paint is men ti oned inthe passage ?(A) It dries quickly(B) It is difficult to make(C) It dissolves easily(D) It has to be applied directly to wood17. The