单项选择题
A．Because TV programs are not interesting. B．Because TV viewers are totally passive. C．Because TV prices are very high. D．Because TV has both advantages and disadvantages.
A．not very convenient B．very expensive C．quite dangerous D．relatively cheap
A．To arouse the reader's concern. B．To introduce the theme of the whole passage. C．To summarize the whole passage. D．To state the primary uses of TV.