How should we understand the social benefits of a sustainable transportation system？
A. It should be efficient.
B. It should be safe.
C. It should be friendly.
D. It should be constructive.
【C15】
A. hand
B. head
C. hands
D. driver
【C12】
A. send
B. sending
C. to send
D. sent
Smoking is not______in such public places as the theater, the library and the museum.
A. let
B. permitted
C. promised
D. agreed
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