这是一个被动语态,先去掉附加的定语从句we are going to see this evening 为: The moviewas said to be based on a true event. 这部电影曾被认为基于一次真实事件( be said to be 表示“被认为是”) 改回到主动语态为:People said the movie to be based on a true event. (movie 是宾语,不定式to be based on a true event是宾补),意思是“人们曾经认为这个电影立基于一次真实事件的”。 如果用现在时,句子就成了People say the movie to be base...