Priscilla Ouchida's"energy-efficient" house turned out to be a horrible dream.When sheand her engineer husband married a few years ago,they built a$100,000,three-

bedroom home inCali-fornia._________(46)

Problems began assoon as the couple moved in,however. Priscilla's eyes burned._________ (47)Shesuffered from headaches and could hardly sleep.It was as though she had

suddenly developed astrange illness.

Experts finallytraced the cause of her illness.The level of formaldehyde（甲醛）gas in her kitchen was twice themaximum allowed by federal standards for chemical

workers.The sourceof the gas?__________(48)

The Ouchidas arevictims of indoor air pollution,which is not given sufficient attention partlybecause of the nation's drive to save energy.The problem itself isn'tnew."The

indoor environmentwas dirty long before energy conservation camealong,"__________(49)"Energy conservation has tended to accentuatethe situation in some cases."

The problem appearsto be more troublesome in newly constructed homes rather than old ones. Back inthe days when energy was cheap,home builders didn't worry much

about unsealedcracks. __________(50)As a result,the pollutants generated in most householdsseldom build up to dangerous levels._________（49）

A.Her new kitchencabinets and wall-to-wall carpeting.

B.Because of suchleaks,the air in an average home was replaced by fresh outdoor air about oncean hour.

C.The level offormaldehyde gas should be controlled.

D.Her throat wasconstantly dry.

E.saysMoschandreas,a pollution scientist at Geomet Technologies in Maryland.