出处：按学科分类—语言、文字 中国对外翻译出版公司《汉英成语词典》第255页（239字）
指只有口说，不足为据，例这笔生意虽已经双方同意，但口说无凭，一定要订立书面契约，才能保障彼此的权益。
Though this business has been verbally agreed to on both sides，a written con tract has to be signed to protect the rights of both parties．