英语 › 必修第二册 › 必二 U3 › 被动语态
主语是动作的承受者,且动作已经完成或一直持续到现在,用 have / has been done。
Many trees have been planted this year.(今年已经种了很多树。)
关键词:被动语态、passive voice、现在完成时的被动语态、have been done、present perfect passive