A.alternative B.approach C.cast D.challenging E.decorative F.efficient G.electrified H.identify I.photographed J.professionals K.quality L.replaced M.stimulate N.symbolizes O.volunteers Neon ( 霓虹 ) is to Hong Kong as red phone booth sare to London and fog is to San Francisco. When night falls, red and blue and other colors __1__ a hazy ( 雾蒙蒙的 ) glow over a city lit up by tens of thousands of neon signs. But many of them are going dark, __2__ by more practical, but less romantic, LEDs ( 发光二极管 ). Changing building codes, evolving tastes, and the high cost of maintaining those wonderful old signs have businesses embracing LEDs, which are energy __3__ , but still carry great cost. "To me, neon represents memories of the past," says photographer Sharon Blance, whose series Hong Kong Neon celebrates the city's famous signs. "Looking at the signs now I get a feeling of amazement, mixed with sadness." Building a neon sign is an art practiced by __4__ trained on the job to mold glass tubes into__5__ shapes and letters. They fill these tubes with gases that glow when __6__ . Neon makes orange, while other gases make yellow or blue. It takes many hours to craft a single sign. Blance spent a week in Hong Kong and __7__ more than 60 signs; 22 of them appear in the series that capture the signs lighting up lonely streets—an __8__ that makes it easy to admire their colors and craftsmanship. "I love the beautiful, handcrafted, old-fashioned __9__ of neon," says Blance. The signs do nothing more than __10__ a restaurant, theater, or other business, but do so in the most striking way possible.