单项选择题
Which of the following is an appropriate title for the passage（）
A．The Family Life of Americans. B．Public Service and Advertisers. C．The Influence of Advertising. D．Brand Names and Public Pleasure.
单项选择题 The word "convince" in the passage means （）
单项选择题 According to the passage, magnesium was first obtained from （）
单项选择题 47（）
