It's ...that ... 是最平常的句式,一看就知道就是强调句。 强调句你要看清楚,that后面的句子是不是在说同一件事情或一个人。比如,man,后面的he was twenty years ago.说的是同一个人。所以它是强调句 。总之是强调这个主语。 不填who是因为后面的句子是he was twenty years ago. (懂吗 ?)
在限定性定语从句中,如果关系代词在SVC结构中作主语补足语(即表语)时,通常用that. I am the person that i want to be. She was not the person that i thought she was. She is not the pretty girl that she used to be.