difficultadj.困难的;艰难的;(人)难对付的;不易相处的
differentialadj.差别的;特定的;微分的n.差别;工资差额;差动齿轮;[数]微分
differentiatedadj.分化的动词differentiate的过去式和过去分词.
differentiate ofvt.表示异议(提出反对)
differentiated by差别在于; 按 ... 来区分
differentiated race分化型族,分化种
differentiated cell变异细胞, 分化细胞