n.保留，保持，维持防护；v.保持( retain的现在分词 )；拦住；保存；止住 双语释义：v.(动词)vt. 保持; 保留 keep; continue to have or holdvt. 挡住 keep in place英英释义： retain[ ri'teiniŋ ]v.hold within"This soil retains water"; "I retain this drug for a long time"allow to remain in a place or position"S