______ native to North America, corn has now spread all over the world.
A. In spite of
B. That it is
C. It was
D. Although
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Which of the following best states the main idea of the passage（）
A. Noise is a major problem; most people recognize its importance.
B. Although noise can be annoying, it is not a major problem.
C. Noise is a major problem and has not yet been recognized as such.
D. Noise is a major problem about which nothing can be done.
32（）
A. outdoor
B. outing
C. outside
D. outgoing
All the flights ______ because of the snowstorm, we had to take the train instead.
A. were canceled
B. had been canceled
C. having canceled
D. having been canceled
The bicycles have been shipped to all the following places EXCEPT ______.
Africa
B. Latin America
C. the Caribbean
D. Southern Asia
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