单项选择题

Why should anti-virus software be updated at least once a week

A．Because the newly published anti-virus software is more expensive.
B．Because the previous(先前的) anti-virus software cannot work any longer.
C．Because the inventors of viruses have suggested this idea.
D．Because computer viruses are always developing.

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热门试题

单项选择题

Which of the following is NOT right according to the passage

A．Something can be done to keep our computers safe.
B．Even an e-mail attachment coming from a friend may not be safe to open.
C．We should not use our computers to defend ourselves from viruses.
D．Anti-virus software made some years ago is hard to protect today's computers.

单项选择题

Which of the following about doctor medicine is TRUE according to the passage

A．It has a longer history than folk medicine.
B．It has been practiced for around 1,600 years.
C．It bases its treatments on observation and logic.
D．It was very successful in curing sicknesses in ancient times.