on prep.在...之上;由...支撑着;在(某一天);关于;基于adv.穿着;向前(移动);表示持续性adj.表示已连接、处于工作状态或使用中;发生;值班
详细释义
Noun:
enigmatic small elongated wormlike terrestrial invertebrates of damp dark habitats in warm regions; distinct from the phylum Annelida; resemble slugs with legs and are sometimes described as the missing link between arthropods and annelids