找出下列单词中不同类的一项
(______)1. A. on B. where C. behind D. under
(______)2. A. car B. boat C. cat D. ball
(______)3. A. where B. what C. who D. she
(______)4. A. boy B. teacher C. girl D. bag
(______)5. A. desk B.cat C. chair D. bag
(______)6. A. pencil B. ruler C. dog D. eraser