at a time when immigrants were being taken advantage of in frightful ways,这里of in 怎么理解

at a time when immigrants were being taken advantage of in frightful ways,这里of in 怎么理解
at a time when immigrants were being taken
advantage of in frightful ways,这里of in 怎么理解,为什么不直接用in frightful ways,为什么要加个of
原文一段是
Although some criticism was directed at
Ford for involving himself too much in the personal lives of his employees,
there can be no doubt that,at a time when immigrants were being taken
advantageof in frightful ways,Henry Ford was helping many people to
establish themselves in America.