Ⅰ. 将下列各句转换成非谓语动词作定语
1. The building which was built last year is our classroom building.
→The building built last year is our classroom building.
2. The book which was published ten years ago is still a best-seller today.
→The book published ten years ago is still a best-seller today.
3. What will you do with the paper that has been used?
→What will you do with the used paper?
4. How can the doctors who are working in the operation room protect themselves?
→ How can the doctors working in the operation room protect themselves?