9．As I enter my 40s，I've noticed many of my parents'generation think social networking is something they are simply incapable of understanding．They fear that，should they try，they will somehow get it wrong； they will say the wrong thing，do the wrong thing or behave in a way that causes embarrassment．But here's the first secret of social media：Everyone feels this way．
I recently met a young actor who was complaining that her work demands that she join Microblog，but she always feels like she doesn't have anything smart to say．It's the same resistance I hear from the older generation，who，however，have somehow convinced themselves that age is the barrier，rather than the differences of individual taste．
Here's the second secret of social media：everybody uses it for more or less the same reasons．Older generations often sign up to stay in touch with children and relatives．We talk about this kind of contact like it's some old-fashioned activity，but it is exactly why younger people use social media．The truth is most people use social media to gently keep an eye on one another，to see how those they care about are doing without needing to ring them up on the phone every night．
And this is the last secret of social media：everyone gets to use it their own way．Newcomers-younger and older-who worry about"getting it right"are assuming that there's a right way to get it．But actually there isn't．Personally，I talk a lot on Microblog．And some people post nothing and they use social media everyday as readers．Social media companies would rather see people pumping their networks full of pictures and posts，but there's no rule against being a fly on the wall．It's also a fine way to engage．
We're quick to forget that the web wasn't invented by 13-year-olds； it was created by today's seniors．I'd never try forcing those with no interest on social networks to use Microblog．But don't let the talk of age divides put you off．There's nothing to stop the older generation from re-taking the network their own generation created．
47．What's the author's purpose of writing this passageD？
A．To share with us his personal experience using social media．
B．To tell us a few secrets of social media that he discovered．
C．To explain why the old generation don't use social media．
D．To relieve the old generation from fearing using social media．
48．The expression"a fly on the wall"in the 4
th paragraph refers toB．
A．people who promote reading online books
B．people who only observe others'posts
C．people who cause trouble to others
D．people who post many pictures
49．According to the author，which is a reason for old people's fear using social mediaA？
A．They believe that they may fall into embarrassing situations．
B．They prefer to stay in touch with relatives in real life．
C．They have no interest in social networking．
D．They have no idea what to post online．
50．Which of the following may best describe the structure of this passageB？
