第三人称单数
现在分词
过去式
过去分词
Security at royal residences had already been stepped up after an Australian writer paraglided onto the forecourt of the Queen's central London home Buckingham Palace on 28 December.
BBC: Alert as palace security breached
英汉双解词典包含3185865条英汉词条，基本涵盖了全部常用单词的翻译及用法，是英语学习的有利工具。