6. In his research at Columbia University, Charles Townes worked with all of the following EXCEPT

　　(A) stimulated emission

　　(B) microwaves

　　(C) light amplification

　　(D) a maser

　　7.In approximately what year was the first maser built?

　　(A) 1917

　　(B) 1951

　　(C) 1953

　　(D) 1957

　　8. The word "emerged" in line 20 is closest in meaning to

　　(A) increased

　　(B) concluded

　　(C) succeeded

　　(D) appeared

　　9. The word "outlining" in line 21 is closest in meaning to

　　(A) assigning

　　(B) studying

　　(C) checking

　　(D) summarizing

　　10. Why do people still argue about who deserves the credit for the concept of the laser?

　　(A) The researchers’ notebooks were lost.

　　(B) Several people were developing the idea at the same time.

　　(C) No one claimed credit for the development until recently.

　　(D) The work is still incomplete.

　　Question 11——21

　�。牐� Panel painting, common in thirteenth -and fourteenth -century Europe , involved a

　　painstaking , laborious process. Wooden planks were joined, covered with gesso to

　　prepare the surface for painting , and then polished smooth with special tools. On this

　　perfect surface, the artist would sketch a composition with chalk, refine it with inks,

　　and then begin the deliberate process of applying thin layers of egg tempera paint (egg

　　yolk in which pigments are suspended) with small brushes. The successive layering of

　　these meticulously applied paints produced the final, translucent colors.

　�。牐燘ackgrounds of gold were made by carefully applying sheets of gold leaf, and then

　　embellishing of decorating the gold leaf by punching

　　it with a metal rod on which a

　　pattern had been embossed. Every step in the process was slow and deliberate . The

　　quick-drying tempera demanded that the artist know exactly where each stroke be

　　placed before the brush met the panel, and it required the use of fine brushes. It was,

　　therefore , an ideal technique for emphasizing the hard linear edges and pure, fine areas

　　of color that were so much a part of the overall aesthetic of the time. The notion that an

　　artist could or would dash off an idea in a fit of spontaneous inspiration was

　　completely alien to these deliberately produced works.

　�。� Furthermore, making these paintings was so time-consuming that it demanded

　　assistance. All such work was done by collective enterprise in the workshops. The

　　painter or master who is credited with having created painting may have designed

　　the work and overseen its production, but it is highly unlikely that the artist’s hand

　　applied every stroke of the brush. More likely, numerous assistants, who had been

　　trained to imitate the artist’s style, applied the paint. The carpenter’s shop probably

　　provided the frame and perhaps supplied the panel, and yet another shop supplied the

　　gold. Thus, not only many hands , but also many shops were involved in the final

　　product.

　　�牐營(yíng)n spite of problems with their condition, restoration, and preservation many panel

　　paintings have survived, and today many of them are housed in museum collections.