23．The computer center，that was opened last year，is very large．

22．Miss Li，who you met，is our English teacher．

21．As you know it，he has left for America．

20．He has three sons，two of them are music lovers．

18．It was the meeting which importance I didn’t know．

　　 1 9．My father，that has been away recently, wants to see you．

15．This is the necklace for which she is looking．

　　 1 6．Do you still remember the day which you joined the Party?

　　 1 7．This is the boy his handwriting is the best in our class

12．Father came back on April 4th when was my birthday．

1 3．Is this factory which you set up yourselves?

　 1 4．Is this the city where you visited last year?

11．He has written a book．the name of it I have forgotten．

10．I shall never forget the days when I spent with you·

9．Who is the man who is speaking to your mother?