Question

5. For years people thought he was a rich businessman,         that he was a skilled thief (turn)

多年来人们认为他是一个有钱的商人，但后来证明他是一个老练的窃贼。

Answer 1

5. but it turned out it turned out that...是固定句式，意为"后来证明为……"，其中it是形式主语，代替后文中真正的主语从句that...。 turn out为不及物动词短语，不可用于被动语态中。