(     )1.--- Did anyone hurt in the accident?   --- Yes. Jack is the boy ________ arm was hurt in the accident.

  A. whose      B. whom      C. which

(     )2.--- Could you tell me _______?    --- In the Song Dynasty.

  A. when was printing invented   B. when printing invented   C. when printing was invented

3. Many _________(发现) were made with the help of compass.

4. Paper-making was developed in the _________(东) Han Dynasty by Cai Lun.

5. The camera was one of the greatest _________________ (发明) in the 19th century.