3. The gas _______ which we can not live is called oxygen.(Find out the meaning of the clause.)

　　巩固拓展

1. The dictionary _____ ______ so many pages are missing is useless.

2. This is the boy ______ ______ we have to say "Thank you".

3. I have not met Mr. Wang, the son ______ ______ is my English teacher.

4. The old couple _____ ______ I lived in Abington were very nice to me

5. That was the period ______ ______ my cousin stayed in my home.

6. The building _______ _______ we held the meeting last year has been pulled down.

7. We are reading a book _______ ______ there are a lot of mistakes

8. John, ________ _______ we talked yesterday, is from Canada.

☆Assignment

Preview the instructions on page 30.

Finish related exercises.