在英语的被动语态中，be动词的省略通常发生在以下几种情况：
状语从句的主语与主句主语相同，且状语从句谓语为被动语态时，可以省略从句的主语和be动词。例如：“The book was read by her.” 可以简化为 “The book read by her.”。
当主语是“it”时，谓语“be”动词可以被省略。例如：“It was said that he was coming.” 可以简化为 “Said he was coming.”。
句子中的主语和谓语动词之间有其他限定语，如副词或介词短语时，谓语“be”动词也可以被省略。例如：“The book was written by John in 2005.” 可以简化为 “The book written by John in 2005.”。
当谓语动词是不及物动词时，谓语“be”动词也可以被省略。例如：“The children were playing in the park.” 可以简化为 “The children playing in the park.”。
过去分词作后置定语时，be动词可以被省略。例如：“The boy called Tom is my friend.” 可以简化为 “The boy who is called Tom is my friend.”。
作并列谓语时，后面动词的被动语态中的be常省略。例如：“The song is written and sung by the man over there.” 可以简化为 “The song was written and was sung.”。
在进行时态中，当主语是第三人称单数时，be动词可以省略。例如：“The book is being read by her.” 可以简写成 “The book being read by her.”。
在完成时态中，当主语是第三人称单数时，be动词也可以省略。例如：“The letter has been written by him.” 可以简写成 “The letter written by him.”。
被动非谓语省略be动词，例如过去分词作为定语时，过去分词可以用来修饰名词或代词，来表达被动语态的意思。例如：“The book written by her is excellent.”。
总的来说，be动词的省略在英语被动语态中是一种常见的简化句子的方式，但使用时要根据具体的语境来判断是否合适。
