选出与其他两个单词不同类的一项。 ( )(1)A. ruler B. fish C. hen ( )(2)A. this B. that C. is ( )(3)A. Yes B. No C. not ( )(4)A. activity book B. story book C. pen ( )(5)A. cow B. horse C. animal ( )(6)A. camera B. fan C. elephant ( )(7)A. boy B. girl C. fan ( )(8)A. it B. who C. he