Read the following passage, and mark the letter (A, B, C or D) on your answer sheet to indicate the correct answer for each of the blanks.
Last summer, air pollution in Paris reached dangerous levels on six separate occasions. As a result, the government have recently decided that public transport in French cities will be (6) ______ on days when pollution becomes a (7) ______ to people’s health, in a(n) (8) ______ to encourage people to leave their cars at home.
The major of Paris said that he had several other ideas to reduce the pollution problem, such as free parking on the (9) ______ of the city on hot, still days when exhaust fumes tend to accumulate. He has also announced a $6 million plan for 56 km of bicycle tracks, new pedestrianised zones and a new tram line for southern Paris. His most popular measure (10) ______ becoming mayor last May has been to (11) ______ traffic from several streets on Sundays.
Every summer, air quality is at its (12) ______ in Paris during holiday weekends, especially one weekend in July when the (13) ______ of the population leave by car for their summer holidays. Conditions then improve for the summer, but deteriorate again when most residents return at the end of August.
The free transport (14) ______ is part of the respond to a new environmental regulation which says that local authorities must guarantee safe air. If it is (15) ______ seriously, local can look forward to a cleaner Paris in the future.
A.as
B.since
C.from
D.then