Passage Three
Questions 32 to 35 are based on the passage you have just heard.

A．The plane is delayed by the late arrival of some passengers.
B．The plane is delayed by some mechanical failure.
C．The weather does not allow the plane to take off.
D．The luggage of some passenger is dangerous.

A．There is no greenhouse gas now, since it has been well under control.
B．Now the production of CFCs used in refrigerators is only one third of that in the mid- 1980s.
C．Oxides of sulfur can lead to acid rain and smog.
D．The amount of lead, soot and carbon monoxide that are sent out has been reduced sharply.