A．aheadB．awayC．offD．out
A. ahead
B. away
C. off
D. out
Duty is an act or a course of action that people ______ you to take by social customs, law
A. persuade
B. request
C. instruct
D. expect
According to the text, what is the major cause of the flooding spam？
A. Companies rely on e-mails for communications.
B. More people in the world communicate by e-mails.
C. Many computer viruses contain spam e-mails.
D. More advertisers begin to promote sales through spam.
A．unemploymentB．challengeC．competitionD．retirement
A. unemployment
B. challenge
C. competition
D. retirement
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