单项选择题

It will be even more difficult to develop a vaccine because______.

A．most women are infected by a single variant of the HIV virus
B．the virus can duplicate itself into more genetic variants
C．it is difficult to monitor the activities of the viruses
D．technologies are not advanced now

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单项选择题

A．Earning a LivingB．Correct Attitude on Job-huntingC．How to Choose a JobD．What Can a Good Job Offer

A．Earning a Living
B．Correct Attitude on Job-hunting
C．How to Choose a Job
D．What Can a Good Job Offer

单项选择题

Which of the following is correct

A．Stock options should not be charged against corporate income when they are cashed in.
B．Now stock options is not treated as a company expense and is exercisable for five years.
C．There are national guidelines for all publicly listed companies doing business in the U.S..
D．CEOs and CFOs must account for accuracy of financial statements but for critical underlying trends.