For example, one who doesn't know the rules a about plagiarism (剽窃) may accidentally use words or ideas without giving proper credit or one who fails to keep careful research notes may unintentionally fail to quote and cite sources as required.
出自-2011年12月阅读原文
英语六级真题
Originally from South America, the snails were accidentally introduced into the Ebro Delta by Global Aquatic Technologies, a company that raised the snails for fresh-water aquariums, but failed to prevent their escape.
2018年6月六级真题(第二套)阅读 Section C
柯林斯高阶英汉双解学习词典释义
ADJ
意外的;偶然(发生)的
An accidental event happens by chance or as the result of an accident, and is not deliberately intended.