The market investigation is indispensable to sales promotion.
The writer wanted to resign because（）
A. he had serious trouble with his boss
B. he got underpaid at his job for the Globe
C. he wanted to be engaged in the new media industry
D. he had found a better paid job in a publishing house
3（）
A. and
B. but
C. or
D. so
The selection says that computers play an essential roles in （）.
A. automation processes
B. mathematical computations
C. traffic control
D. the development of mathematical theory
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