yán / jiū / rén / yuán / zài / dòu / kē / zhí / wù / de / gēn / bù / fā / xiàn / le / xǔ / duō / gēn / liú研究人员在豆科植物的根部发现了许多根瘤。The researchers found many root nodules on the roots of leguminous plants.