A．By searching the network siteS.
B．By examining the cookies on user computers.
C．By sending emails to the users.
D．By consulting computer companies.
A．Cell phones of poor quality.
B．Annoying ads.
C．Spring sandals of outdated style.
D．Excessive morning news.
A．It will be rooted out in a few years.
B．It benefits net users in many ways.
C．It invades the privacy of net users seriously.
D．It exists in almost all the websites.