填空题

Questions 47 to 51 are based on the following passage.
When Toyota Motor Corp. moved one of its divisions into an environmentally friendly, or“green”, building in Torrance three years ago, it expected to save on its energy bills. The building offered natural lighting, electricity-generating rooftop solar panels and water recycling.
But something else also happened. Employee morale jumped while absenteeism(旷工) fell. The overall energy and worker productivity savings more than offset the added cost of making the facility environmentally friendly. “The lighting is easier on the eyes and on the nerves, ”Toyota employee Mary Jo Moutsios said. “I take a sense of pride in working in this building. It’s pleasant and feels more productive. ”
Results like Toyota’s are helping to spark a budding“green revolution”in American workplaces. The movement is starting to change how office buildings are designed and could render thousands of existing offices obsolete.
Employers including Goldman, Sachs&Co. , Wal-Mart Stores Inc. and Harley-Davidson Inc. are starting to ask for buildings with more natural light, fresher air and fewer toxic materials in the paint, carpeting and other finishes. Los Angeles, Salt Lake City and Chicago are among many cities requiring new public buildings to be green. Municipalities are offering incentives, such as faster construction approvals and reduced permit fees, to get the private sector to follow suit.
Although the green movement is in its infancy, its endorsement(认可) by a growing number of prestigious employers, developers and cities is seen as giving a shot in the arm to the nation’s environmental movement as concern about the effects of global warming and environmental pollution spread.
More than $7.7 billion of office buildings nationwide are up for official green certification, versus about $790 million in 2000．Among the more notable new green towers is World Trade Center in New York. a 52-storey skyscraper that replaced a building at the same address that was destroyed in the 2001 terrorist attacks.
Although making the facility environmentally friendly added the cost of the Toyota Motor Corp. , the savings from using green facilities can______.