In the last 15 years:
A. the pollution control system has reached its goals.
B. the pollution control system has failed entirely.
C. some environmental problems have proven to be more intractable than originally thought.
D. concern for the environment has declined considerably in most parts of the country.
Question 2
Since the 1960s air quality has:
A. gotten much worse.
B. improved noticeably.
C. stayed about the same.
D. none of the above