1. The earthquake          shook the city in 1906 was the biggest in American history.

2. We don't know the number of people___________ lost their homes in the 1906 earthquake.

3. The house            they built in 1987 is still very new.

4. The house            is built on sand may fall down in an earthquake.

5. Luckily none of the people          I know were killed.

6. The boy          father is a teacher is very clever.

7. A clock is a machine           tells people the time.

8. A fridge is a machine          is used for keeping food fresh.

9. April 1 is the day          is called April Fool's Day in the west.

10. The house           he is looking for is very expensive.

11. This is the factory           we visited the day before yesterday.

12. My friends Enoch will never forget the teacher         taught him English at Bell School.