52．C．细节理解题．根据It was to help students get in touch with each other over the Internet．可知脸书的建立是为了帮助学生之间进行联系的．故选：C．
53．B．词义猜测题．根据Facebook has given people a safe and trusted environment to -online．可知脸书给人们提供了一个安全可靠的网上互动交流的环境．故选：B．
54．A．细节理解题．根据Facebook is different from other social networking sites because you can communicate with people you really know and trust．脸书不同于其他的社交网站是因为你能在脸书上跟认识的，可信的人进行交流，所以比较安全．故选：C．
55．C．正误判断题．根据More than half of its users are not at college anymore and the fastest growing group are the 30 to 40 year olds．可知一半多的用户不再再大学，快速增长的用户年龄在30至40岁的．可知C项的陈述是错误的．故选：C．
56．A．主旨大意题．根据It was back in February 2004 when Zuckerberg started"The facebook"from a Harvard student's room．和Today it has 800 million active users．可知脸书2004年在哈佛大学的学生宿舍开办到现在已有8亿的用户．可知这篇文章主要讲述了脸书的发展．故选：A．
标签：Facebook,world,biggest
