定级把杂种劣种动物与纯种杂交改良与up连用级进杂种级用于动物分类品种被改良与up连用
Gradation The hybridization of an inferior breed of animal with a purebred hybrid for use with up The gradation of a hybrid is used for the classification of animals in which a breed is improved for use with up
以上为机器翻译结果，长、整句建议使用 人工翻译 。