单一: single; unitary; singleness; singlet; unity 短语和例子单一的生产资料全民所有制 a unitary system of the ownership of the means of production by the whole people
品种退化: degeneration of seed strainsdegeneration of varietydegradation of breeddegradation of varietydeterioration of strainsdeterioration of varietystandard aberrationvariety degeneration
