英语四级考试中的阅读部分历来是中国学生的薄弱环节。为了帮助考生能够在这部分有所突破，编辑老师整理了这篇14年12月英语四级阅读辅导：定义题，希望对大家有所帮助！
Priscilla Ouchida's “energy-efficient” house turned out to be a horrible dream. When she and her engineer husband married a few years ago, they built a $ 100,000 three-bedroom home in California. Tightly sealed to prevent air leaks,the house was equipped with small double-paned (双层玻璃的)windows and several other energy-saving features. Problems began as soon as the couple moved in,however. Priscilla’s eyes burned. Her throat was constantly dry. She suffered from headaches and could hardly sleep. It was as though she had suddenly developed a strange illness.
Experts finally traced the cause of her illness. The level of formaldehyde (甲酵)gas in her kitchen was twice the maximum allowed by federal standards for chemical workers. The source of the gas? Her new kitchen cabinets and wall-to-wall carpeting.
The Ouchida are victims of indoor air pollution, which is not given sufficient attention partly because of the nation s drive to save energy. The problem itself isn't new. “The indoor environment was dirty long before energy conservation came along,” says Moschandreas, a pollution scientist at Geomet Technologies in Maryland. Energy conservation has tended to accentuate the situation in some cases. ”
The problem appears to be more troublesome in newly constructed homes rather than old ones. Back in the days when energy was cheap,home builders didn’t worry much about unsealed cracks. Because of such leaks?the air in an average home was replaced by fresh outdoor air about once an hour. As a result, the pollutants generated in most households seldom built up to dangerous levels.