请根据短文内容，回答题。 Saving a City"s Public Art Avoiding traffic jams in Los Angeles may be impossible, but the city&39;s colorful freeway murals ( 壁画 ) can brighten even the worst commute. Paintings that depict (描述) famous people and historical scenes cover office buildings and freeway walls all access the city. With a collection of more than 2,000 murals, Los Angeles is the unofficial mural capital of the world. But the combination of graffiti (涂鸦), pollution, and hot sun has left many L.A. murals in terrible condition. __________ (46) in the past, experts say, little attention was given to caring for public art. Artists were even expected to maintain their own works, not an easy task with cars racing by along the freeway. __________ (47) The work started in 2003. So far,16 walls have been selected and more may be added later. Until about 1960, public murals in Los Angeles were rare. But in the 1960s and 1970s, young L.A. artists began to study early 20th-century Mexican mural painting. __________ (48) The most famous mural in the city is Judith Baca&39;s "The Great Wall", a 13-foot-high(4-meter-high) painting that runs for half a mile (0.8 kilometer) in North Hollywood.__________ (49) it took eight years to complete--400 underprivileged teenagers painted the designs--and is probably the longest mural in the world. One of the murals that will be restored now is Kent Twitchell&39;s "Seventh Street Altarpiece" which he painted for the Los Angeles Olympics in 1984. __________ (50) Twitchell said, "it was meant as a kind of gateway through which the traveler to L.A. must drive. The open hands represent peace." Artists often call murals the people&39;s art. Along a busy freeway or hidden in a quiet neighborhood, murals can teach people who would never pay money to see fine art in a museum," Murals give a voice to the silent majority," said one artist. 第46题___________ 查看材料 A.The city trying to stop the spread of graffiti， has painted over some of the murals complete.