已知平面直角坐标系上有6个点:A(3,3),B(1,1),C(9,1),D(5,3),E(-1,-9),F(-2,-
①甲类含两个点,乙类含其余四个点 甲类:点______、______是同一类点,其特征是______;乙类:点______、______、______、______是同一类点,其特征是______. ②甲类含三个点,乙类含其余三个点 甲类:点______、______、______是同一类点,其特征是______;乙类:点______、______、______是同一类点,其特征是______. |