12． （1）A.A search engine developed by a library.
B.An introduction to the Pearl Library.
C.A person﹣to﹣person information service.
D.Changes that search engines bring to us.
（2）A.It may give you a large number of results.
B.It may cause your computer to break down.
C.It will provide unreliable information.
D.It will take a long time to show the answers.
（3）A.It recommends what to read when you miss key information.
B.It offers a satisfactory answer even to a vague question.
C.It teaches you how to look for information.
D.It is accessible for 9 hours 7 days a week.
参考答案
B A B