12.In the dark street,there wasn't a person____________________she could turn for help.
13.It was the school____________________we got to know each other.
14.China has thousands of rivers,the longest____________________is the Changjiang River.
15.The age____________________children can go to school is seven.
16.His bike____________________he went to work was stolen last night.
17.Who is the girl____________________Mary is talking.
18.Do you know the building____________________is flying a red flag.
19.Did you attend the meeting yesterday____________________our teacher talked a lot.
20.Ours is a beautiful school,____________________we are proud.
21.The desk____________________Jack is leaning is John's.
22.The farm____________________my father once worked has taken on a new look now.
23.He bought a book yesterday,the author____________________is a teacher.
参考答案
12.to whom 13.in/at which 14.of which 15.at which 16.on which 17.to/with/about whom
18.over which 19.at which 20.of which 21.against which 22.on which 23.of which