2009年12月大學(xué)英語六級(jí)考試模擬演練題(二)

　　Wherever you’re sitting, it will be hard to enjoy a library if you’re suffering from eyestrain, fatigue and headaches, which can all be brought on by poor lighting. When selecting lighting, look for a lamp that will help you see the smallest text you read. The lamp should be positioned over your shoulder, so that the light is not directly in your eyes. Positioning it this way will also help to minimize glare. Your lamp should be brighter than the rest of the room but not that much brighter. However, all light will eventually damage books, so use it at a minimum.

　　Book Care

　　Do you devour books quickly ? You’re not the only one. Some insects love books, but not for a good story. Book-worms are not just those readers that have their nose in a book all the time. The more dangerous kind will tunnel through the book, eat the pages and lay eggs in it.

　　Once you identify an infestation, isolate the affected books. In some cases, you can seal the books in plastic bags and freeze them to kill the insects. Keeping your library free of excess moisture and dust will help to prevent an attack by these insects and vermin (害蟲).

　　Controlling moisture and dust doesn't just keep away the book bugs though . Moisture in the air will also promote the growth of fungus and mold. Mold develops at temperatures greater than 70 degrees Fahrenheit, and with 65 percent relative humidity. Dehumidifiers will suck excess moisture out of the air, moisture that could otherwise lead to loose bindings, stains and mildew. Oppositely, too little humidity can dry out books, so use a humidifier in the drier winter months. Dust is also a magnet for moisture and mildew, so periodically dusting the tops of books will keep them clean.

　　In addition to a humidifier, you also might need a fan to keep the library well ventilated. Books should be stored away from radiators and kept in a room between 60 oF and 70 oF. Air conditioners and fans are fine to use to keep the temperature down. Extreme heat will damage books; if heat occurs in a room with low humidity, the fibers in the books will dehydrate, turning the pages brittle. In combination with high humidity, heat creates ideal growing conditions for mold.

　　As we mentioned in the last section, lighting can damage books because it leads to bleaching (漂白), fading and eventual deterioration. Natural lighting is the most dangerous. If your library has windows, draw the blinds or curtains to minimize injury. Limiting the intensity light and duration of exposure will help to preserve the books.