六、读单词,把它们按照同类别分类,将其标号填在相应的线上。A.rock B.mother C.polit D. father E.niece F. teacher G.Professor H.Steel I.doctor J.nut K. iron L. plant职业:________ ________ ________ ________家庭成员:________ ________ ________建筑材料:________ ________ ________