【简答题】. Birds in cities are damaging their health by trying to sing above the noise of life. New research shows that male birds are trying to compete against traffic and city sounds.They are now singi...
【简答题】The government _____ air quality in areas from level one to five: excellent, fairly good,slightly polluted, poor and erous. A arranges B. classifies C. distributes D. divide...
【单选题】Scientists now tend to agree that the noise level for potential hearing loss begins at about 70 decibels. Some of them are very concerned because normal daily life often exposes people to noise levels...